TRIPLE-JUNCTION A-SI SOLAR CELLS WITH HEAVILY DOPED THIN INTERFACE LAYERS AT THE TUNNEL JUNCTIONS W of Toledo, Toledo, OH 43606 USA ABSTRACT Triple-junction a-Si based solar cells, having a structure of SS cells and between the middle and bottom component cells on the efficiency of triple- ...

United Solar used a-Si:H/a-SiGe:H/a-SiGe:H in two manufacturing plants and improved solar efficiency and reduced manufacturing cost by new deposition methods, optimized deposition parameters, and new materials and cell structures.

a-Si 1-x Ge x :H materials for high performance solar cells. Construction of a new Dual Beam Photoconductivity (DBP) apparatus has been completed, and the new capabilities are...

United Solar Ovonic successfully used its spectrum-splitting a-Si:H/a-SiGe:H/a-SiGe:H triple-junction structure in their manufacturing plants, achieving a manufacturing capacity of 118 MW in 2007, and set up a very aggressive expansion plan to achieve grid parity.

The objectives for the University of Toledo are to: (1) establish a transferable knowledge and technology base for fabricating high-efficiency triple-junction a-Si-based solar cells, and (2) develop high-rate deposition techniques for the growing a-Si-based and related alloys, including poly-Si, c-Si, ...

Nevada Nanotechnology Center and Si group at NREL will work together to develop a-Si based solar cells with nano-Si technique. We will explore the existing a-Si based film solar cell technology at NREL and nano scale Si technology at Nevada Nanotechnology...

A flexible amorphous silicon (a-Si) based photovoltaic (PV) module has been developed. The a-Si solar cell fabricated on a heat-resistance plastic film with a thickness of 50{micro}m has a new monolithic series-connected structure named SCAF to obtain a high output voltage required for practical use. Applying ...

a-Si/a-SiGe/a-SiGe flexible PV products on stainless steel The development of space solar cells on polymer substrate has leveraged the terrestrial technology Green Power...

The use of ethylene (C/sub 2/H/sub 4/) rather than methane (CH/sub 4/) as the source of carbon in the hydrogenated amorphous silicon carbide (a-SiC:H) p/sup +/ layer of hydrogenated amorphous silicon (a-Si:H) based solar cells deposited in a glow discharge has been explored. Device results are presented to ...

also reported. 1. Objectives General project objectives of "The Fabrication and Characterization of High-efficiency Triple-junction a-Si Based Solar Cells" are to establish a...

Nevada Nanotechnology Center and Si group at NREL will work together to develop a-Si based solar cells with nano-Si technique. We will explore the existing a-Si based film solar cell technology at NREL and nano scale Si technology at Nevada Nanotechnology Center. By ...

In high efficiency narrow bandgap (NBG) a-SiGe solar cells, thin buffer layers of unalloyed hydrogenated amorphous silicon (a-Si) are usually used at the interfaces between the a-SiGe intrinsic layer and the doped layers. They investigated the effect of inserting additional a-SiGe interface layers between these ...

A method to form a:Si-H films at high rate and at reduced temperature would be of commercial value in the manufacture of solar cells and of semiconductor devices. A laser-based film formation process was developed, based on multiple infrared photon dissoc...

A simple procedure for the application of a transparent-conducting coating onto a-Si:H devices is described. Results pertaining to a-Si:H solar-cell heterojunctions incorporating such coatings are given and discussed.

distinctly different defects located at 1.0 and 1.2eV from the conduction band. The evolution of these defects under light induced degradation depends on the microstructure of...

the corresponding results from studies of films in which large differences in the evolution of two types of defect states has also been found 1 . The results obtained for the...

Oct 1, 1985 ... of submodules based on thin film amorphous silicon (a-Si) p i n solar cells. Starting from presently attainable single cell characteristics, ...

A two-dimensional numerical computer analysis for thin-film-based hydrogenated amorphous silicon (i.e. a-Si : H) solar cells is presented. A comparative performance assessment for various absorbing layers such as a-Si, a-SiGe, a-SiC, combined a-Si+a-SiGe, ...

We report the antireflective property of thin film amorphous silicon (a-Si) solar cell structures based on graded refractive index structure together with theoretical analysis. Optimizations of the index profile are performed using the rigorous coupled-wave analysis method. The graded refractive index structure fabricated by oblique ...

Mesoporous nanocrystalline ZnO applied to a-Si/mesoporous tandem solar cell was synthesized through the hydrothermal method. The structures and morphologies were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis based on the nitrogen adsorption isotherm. The test results indicated ...

This report describes the research on high-efficiency CdTe-based thin-film solar cells and on high-efficiency a-Si-based thin-film solar cells. Implemented a diode-array spectrograph system and used optical emission spectroscopy to help optimize the react...

The principal objective of this R&D program is to expand, enhance, and accelerate knowledge and capabilities for development of high-efficiency hydrogenated amorphous silicon (a-Si:H) and amorphous silicon-germanium alloy (a-SiGe:H) related thin-film multijunction solar cells and modules with low manufacturing cost and high ...

Thin hydrogenated amorphous silicon (a-Si:H) layers deposited by hot-wire chemical vapor deposition (HWCVD) are used as both emitters and back contacts in silicon heterojunction solar cells. Low interface recombination velocity and high open-circuit voltage are achieved by a low substrate temperature (200 deg C) which appears to improve dopant activation. ...

This summary describes tasks of novel improved intrinsic materials for multijunction solar cells, insights into improved stability in materials and solar cells, optimization of solar cell performance with improved intrinsic layers, and optimization of multijunction solar cells. The report characterizes a ...

Solarex, a business unit of Amoco/Enron Solar, is scaling up its a-Si:H/a-SiGe:H tandem device technology for the production of 8 ft2 modules. The current R&D effort is focused on improving the performance, reliability and cost-effectiveness of the tandem junction technology by systematically optimizing the materials and interfaces in small-area ...

This report describes a 21-month project to demonstrate amorphous-silicon (a-Si) solar cells with high stabilized conversion efficiency. The objective was to develop a research program spanning material issues (more stable a-Si and better a-SiGe alloys) and device issues (more stable a-Si-based ...

SCHOTT Solar a-Si Plant SCHOTT AG said it will spend about $72 million to build a thin-film solar module factory in Jena, Germany. See coverage at RenewableEnergyAccess:

This dissertation summarizes the research work on the investigation and optimization of high efficiency hydrogenated amorphous silicon (a-Si:H) based thin film n-i-p single-junction and multi-junction solar cells, deposited using radio frequency (RF) and very high frequency (VHF) plasma enhanced chemical vapor deposition (PECVD) ...

In this report we present the results for the four principal tasks of this research project: Amorphous Silicon Solar Cell Characteristics and Modeling; Photocarrier Drift Mobility Measurements in hydrogenated amorphous silicon (a-Si:H), microcrystalline s...

This report describes results achieved during phase 1 of a three-phase subcontract to develop and understand thin-film solar cell technology associated to CuInSe(sub 2) and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin fil...

various problems experienced by SMUD' s main a-Si supplier - Fig. 7: East End a-Si BIPV Curtain Wall 7 primarily delays in getting the new CalSolar a-Si PV factory to normal...

Advances in the science and technology of hydrogenated amorphous silicon (a-Si:H, also referred to as a-Si) and the associated devices including thin-film transistors (TFT) during the past three decades have had a profound impact on the development and commercialization of major applications such as thin-film solar cells, digital image scanners and X-ray ...

United Solar Ovonic is world's largest manufacturer of thin film solar laminates that convert sunlight to electricity. In 1997, we attained initial 14.6% and stable 13.0% cell efficiencies using an a-Si:H/a-SiGe:H/a-SiGe:H triple-junction structure, which established the foundation of large volume roll-to-roll production. Since then, the power rating of ...

An experimental and numerical study of a-SiGe:H based solar cells with band gap graded i-layer in the shape of a V is presented. The variation of the location of the band gap minimum has strong influence on the solar cell performance. Comparisons of experimental and simulated data of the dark IV-behavior, IV-curves under illumination ...

A thermally evaporated p-type amorphous tungsten oxide (p-a-WO3) film was introduced as a buffer layer between SnO2 and p-type amorphous silicon carbide (p-a-SiC) of pin-type amorphous silicon based solar cells. Using the Schottky barrier model, it is shown that the p-a-WO3 layer lowered the Schottky barrier height, which enhanced the ...

This report describes work performed by Energy Conversion Devices, Inc. (ECD) under a 3-year, cost-shared amorphous silicon (a-Si) research program to develop advanced technologies and to demonstrate stable 14%-efficient, triple-junction a-Si alloy solar ...

Efficient hydrogenated amorphous silicon (a-Si:H) nip solar cells have been fabricated with all doped and undoped a-Si:H layers deposited by hot-wire chemical vapor deposition (HWCVD). The total deposition time of all layers, except the top ITO-contact, is less than 4 minutes.

This report describes work performed by Energy Conversion Devices, Inc. (ECD) during this phase of this subcontract. ECD researchers have made significant progress in advancing the very high frequency (VHF), high-rate technology. They demonstrated that 8....

Amorphous silicon alloy based triple junction solar cells and modules with initial efficiencies of approximately 11% have been developed. These devices are expected to exhibit less than a 20% loss before stabilizing. An improved transparent front contact and silicon carbide alloys promise to raise conversion efficiencies to 13%--14%.

It is demonstrated that multijunction {ital a}-Si:H-based solar cells are more stable than their single-junction counterparts and that the stability improves as the number of junctions increases. It is further shown that the rate of degradation of multijunction devices can be explained in terms of the rates of degradation of their individual {ital i} ...

Solarex, a business unit of Amoco/Enron Solar, is scaling up its a-Si:H/a-SiGe:H tandem device technology for the production of 8 ft{sup 2} modules. The current R&D effort is focused on improving the performance, reliability and cost-effectiveness of the tandem junction technology by systematically optimizing the materials and interfaces in small-area ...

Papers are presented on efficient multijunction monolithic cascade solar cells, high efficiency silicon solar cells, point contact silicon cells, and space solar cell research. Also considered are photovoltaic power plants, the reliability of photovoltaic modules, the continuous fabrication of amorphous silicon ...

The work carried out by the University of Oregon Under this subcontract focused on the characterization and evaluation of low-gap (a-Si,Ge:H) alloy materials and on issues related to overall stability in the mid-gap (a-SiH) materials. First, researchers characterized an extensive series of Uni-Solar a-Si,Ge:H ...

This research program is directed toward the advancement of understanding of amorphous silicon-based alloys and their use in small area multi-junction solar cells. The program is divided into subtasks on materials research, single-junction solar cell research, and multi-junction solar cell research. In this report ...

In 1997, a new 4 year plan was initiated in order to achieve more specific goals by FY 2000. An outline of the new 4 year program will be discussed with emphasis on Si thin film solar cells. The main objective of the program is to achieve stabilized efficiencies of over 10% for large area a-Si based solar cell ...

This is the final report covering about 42 months of this subcontract for research on high-efficiency CdTe-based thin-film solar cells and on high-efficiency a-Si-based thin-film solar cells. Phases I and II have been extensively covered in two Annual Reports. For this Final Report, highlights of the first two ...

Experimental and theoretical investigations of the growth and properties of doped hydrogenated amorphous silicon (a-Si:H) materials were performed. Controlled doping of laser-induced chemical-vapor-deposited (LICVD) a-Si:H, both n-type and p-type, was achieved, and the resulting films were characterized by a variety of techniques. Representative-quality ...

The effort at University of Delaware during the first three months of a Department of Energy sponsored a-Si program is described. The objectives of the program are to study and improve photovoltaic properties of plasma-deposited a-Si and model a-Si device...

This report documents the results of material development, single- junction solar cell research, and high-efficiency multijunction cell development. High-quality a-Si:Ge:H:F alloys were made with optical band gaps as low as 1.3 eV; high-conductivity micro...

This report describes work on three individual tasks as follows. (1) Electron and hole drift measurements in a-Si(sub 1-x)Ge(sub x):H and a-Si(sub 1-x)C(sub x):H p-i-n solar cells. Multijunction solar cells incorporating modified band gap a-Si:H in a trip...

This report describes work done by the University of Toledo during the first year of this subcontract. During this time, the CdTe group constructed a second dual magnetron sputter deposition facility; optimized reactive sputtering for ZnTe:N films to achieve 10 ohm-cm resistivity and {approximately}9% efficiency cells with a copper-free ZnTe:N/Ni contact; identified Cu-related photoluminescence ...

We report on fabrication of silicon heterojunction (SHJ) solar cells based on Al-backed p-type silicon wafers, with hot-wire chemical vapor deposition (HWCVD) hydrogenated amorphous silicon (a-Si:H) emitter layers. The two-layer emitters are comprised of an extremely thin ({approx}5-nm) intrinsic a-Si:H ...

This paper discusses material requirements for junction layers needed to obtain solar cells with highest possible open-circuit voltages (VOC). In a typical a-Si:H-based ''p/i/n'' solar cell, this includes the transparent conductive oxide (TCO) contact layer, the p-layer, a ''buffer ...

The kinetics of the light-induced degradation of amorphous hydrogenated silicon ({ital a}-Si:H) based single junction solar cells was studied using an accelerated test with light intensity as high as 140 times that of the sun. A simple scaling law between the light intensity ({ital I}) and the exposure time ({ital t}), i.e., {ital ...

This paper discusses material requirements for junction layers needed to obtain solar cells with highest possible open-circuit voltages (V{sub OC}). In a typical a-Si:H-based p/i/n solar cell, this includes the transparent conductive oxide (TCO) contact layer, the p-layer, a buffer layer inserted at the p/i interface, and the surface ...

Integrated amorphous silicon (a-Si) solar panels have been developed and applied to an electric power generating system. The integrated a-Si solar panel consists of 20 integrated type a-Si solar cell modules, each with a size of 10 cm x 10 cm, which were developed for use ...

1 Design and Fabrication of GaInAsP/InP VCSEL with two a-Si/a-SiNx Bragg reflectors C. Levallois, A dielectric Bragg mirrors and a InGaAsP based active region. The dielectric materials are amorphous silicon these materials. Distributed Bragg reflectors based on these dielectric materials quarter wave layers have been

The authors report on the fabrication and stability tests of single junction a-Si:H, and tandem junction a-Si:H/A-Si:H solar cells using the ECR process under high hydrogen dilution (H-ECR process). They show that devices with high fill factors can be made using the H-ECR process. They also report on the stability studies of the ...

of Energy Conversion University of Delaware Newark DE, USA Development of the transparent contact device and characterization techniques driven by need for better...

A hydrogenated amorphous silicon ({ital a}-Si:H) {ital p}-{ital i}-{ital n} solar cell with a two-layer back electrode is proposed. The new type of back electrode consists of a conventional Al layer and an amorphous silicide layer. The properties of amorphous Cr-silicide film and thermal stability of {ital a}-Si:H {ital p}-{ital ...

The numerically simulated performances of two-subcell tandem and three-subcell triple a-Si-based multijunction solar cells are compared. The current-voltage characteristics are calculated using a simulation program which allows for accurate determination of single-junction or multijunction cell response under a monochromatic or global AM1.5 spectrum. The ...

This report describes research on high-efficiency, single-junction, monolithic, thin-film amorphous silicon solar cells in five task areas: a-Si materials; nonsemiconductor materials; a-Si solar cells; monolithic, intraconnected cells and submodules; and ...

United Solar finishes solar cell (deposits 0.25 cm2 p+/ITO top contacts) United Solar measures device performance (plus QE on selected devices) Pure a-Si:H i-layer results (no...

We have performed computer calculations to explore effects of the p/i interface on the open-circuit voltage in a-Si:H based pin solar cells. The principal conclusions are that interface limitation can occur for values of VOC significantly below the built-in potential of VBI of a cell, and that the effects can be understood in terms of thermionic emission ...

The authors investigated the properties of a novel p-type nanocrystalline Si (p-nc-Si) prepared onto p-a-SiC and the effect of using the buffer with an energy bandgap over 1.9 eV at the p/i interface on the performance of p/i/n type amorphous silicon based solar cells. At the initial growth stage of the p-nc-Si onto ...

This approach to a thin-film Si solar cell combines theoretical analysis, growth of thin-film crystalline Si (c-Si) and deposition of amorphous Si (a-Si:H) to form the heterojunction. The PC-1D model predicts a potential efficiency of >15% for a Si thickness of 10 ?m. Liquid phase growth (LPG) of the base-layer c-Si gave carrier ...

Driven by the need for improvement of the economical competitiveness of photovoltaic energy, the feasibility of high-rate (>1 nm/s) amorphous silicon nitride (a-SiNx):H deposited by the expanding thermal plasma (ETP) technique has been explored with respect to the application of the a-SiNx:H as functional antireflection coating on crystalline silicon ...

Photovoltaic research conducted in four areas is described: semiconductor materials, high-efficiency cells, nonsemiconductor materials, and submodules. The major focus of semiconductor materials research was on improving the quality of wide-band-gap a-SiC:H alloys and narrow-band-gap a-SiGe:H alloys. Raman spectroscopy suggested that the alloys are ...

We have developed hydrogenated amorphous silicon (a Si:H) back contacts to both p- and n-type silicon wafers, and employed them in double-heterojunction solar cells. These contacts are deposited entirely at low temperature (

A technique for measuring the electrical characteristics of contacts to doped hydrogenated amorphous silicon (a-Si:H) or other high-resistivity thin-film semiconductors is developed. Experimental results for metal and conductive transparent oxide contacts to both n- and p-type a-Si:H are presented and the significance of these values to ...

Hydrogenated a-Si solar cells were prepared by rf-sputtering. It was found that for a-Si the surface microstructure of sputtered films can be altered by a simple post-deposition etching process and controlled by varying the film preparation conditions. It...

Amorphous hydrogenated silicon (a-Si:H) belongs still to most promising types of semiconductors for its utilization in fabrication of TFTs and thin film solar cell technology due to corresponding cheap a-Si:H-based device production in comparison with, e.g. crystalline silicon (c-Si) technologies. The contribution deals with both two ...

The use of polymers in solar cells shows great promise for achieving high power-conversion efficiencies at low cost. Polymers have the distinct advantage of being easily solution-processable, while possibly having larger absorption coefficients than conventional inorganic semiconductors. Thus, small amounts of cheaply-processed polymer can be used to make inexpensive ...

This report presents results of the third phase of research on high-efficiency, single-junction, monolithic, thin-film a-Si solar cells. Six glow-discharge deposition systems, including an in-line, multichamber system, were used to grow both doped and undoped a-Si films. In single load-lock systems, a-Si was ...

The goal of this project is to determine the fundamental growth mechanisms of hydrogenated amorphous silicon (a-Si:H) and related alloys. This is important because thin films of these materials must have the high quality and stability required for 15%-efficient solar cells and be produced at high rates and low cost over large areas: achieving these ...

This work presents first results of potential manufacturing processes for integrated series connected hydrogenated amorphous silicon (a-Si:H) thin film solar modules and/or pin-diode/TFT based macroelectronic circuits on flexible tapes. A RTR (Reel-To-Reel) deposition system on laboratory scale has been built. The system consists of ...

This report describes studies on glow discharge (GD) and hot-wire a-Si-based samples by the University of North Carolina-Chapel Hill during Phase I. We have characterized H-bonding and its light-induced changes by using infrared (IR) and differential IR (DIR). For the less stable film, there is a simultaneous decrease {approx} 2040 cm{sup -1} and increase {approx} 1880 cm{sup ...

Hydrogenated amorphous silicon (a-Si:H) is a semiconductor that can be used for thin film solar cells. In the work the properties of a-Si:H that are relevant to the performance of a-Si:H solar cells are studied. The scope of the thesis is the optical prop...

DEVICE PERFORMANCES AND SIMULATIONS FOR SEVERAL KINDS OF LARGE-SCALE THIN FILM SILICON SOLAR CELL MODULES -INTRODUCTION OF SUPER SEE-THROUGH THIN FILM SOLAR CELL MODULE AND...

The influence of atmospheric contaminants oxygen and nitrogen on the performance of thin-film hydrogenated amorphous silicon (a-Si:H) solar cells grown by plasma-enhanced chemical vapor deposition at 13.56 MHz was systematically investigated. The question is addressed as to what degree of high base pressures (up to 10-4 Torr) are ...

This report describes work performed by Energy Conversion Devices, Inc. (ECD) under a 3-year, cost-shared amorphous silicon (a-Si) research program to develop advanced technologies and to demonstrate stable 14%-efficient, triple-junction a-Si alloy solar cells. The technologies developed under the program will then be incorporated into ...

Nanophotonic structures have attracted attention for light trapping in solar cells with the potential to manage and direct light absorption on the nanoscale. While both randomly textured and nanophotonic structures have been investigated, the relationship between photocurrent and the spatial correlations of random or designed surfaces has been unclear. Here we systematically ...

We report two investigations conducted by using photoconductivity decay lifetime measurement. The first is crystalline silicon (c-Si) surface passivation using quinhydrone/methanol (QM) for bulk minority-carrier lifetime measurement. QM shows great promise as a substitute for iodine-based solutions because of its superior stability and minimized surface-recombination velocity ...

Using quartz substrates, hydrogenated a-Si thin films have now been produced both by glow discharge decomposition of silane and by the controlled ion plating of high purity through glow discharges composed of silane, hydrogen, and argon using a modified Takagi apparatus. Thus far, thin films produced by both glow discharge decomposition of silane with and without magnetic ...

Using quartz substrates, hydrogenated a-Si thin films have now been produced both by flow discharge decomposition of silane and by the controlled ion plating of high purity silicon through flow discharges composed of silane, hydrogen, and argon using a modified Takagi apparatus. Thus far, thin films produced by both glow discharge decomposition of silane with and without ...

A method is presented to characterize the TCO/p contact and the TCO sheet resistance in a-Si based p-i-n superstrate devices. It requires having scribed TCO strips, which are electrically isolated before a-Si deposition, then fabricating rows of individual devices on each strip. Analysis of 4-terminal measurements in different V-sensing configurations ...

used in characterizing both the degradation as well as its relaxation. In addition, automation of the experimental procedures enhances the precision of the measurements as well as...

from localized to extended states, were assumed to be constant. Electron spin resonance experiments were conducted with a Bruker Instruments ESR spectrometer with samples...

Two main technologies for low cost solar cells using amorphous silicon (a-Si) film have been developed. A new PCVD (Plasma Chemical Vapor Deposition) fabrication process in which p,i, and n layers of a-Si are deposited in consecutive, separated reaction chambers, has been developed. In this process, high quality a-Si films are ...

This report describes continuing studies on electroluminescence (EL), field profile, and hydrogen microstructure by the University of North Carolina, Chapel Hill, during the third year and the extension period. Based on systematic studies of the EL, the authors developed a complete model to explain the unique features of the EL as dispersive-transport-controlled, non-geminate ...

During the past year, approximately 300 large-area (400 cm exp 2 ) PIN hydrogenated amorphous silicon (a-Si:H) solar cells were fabricated and tested. a-Si:H PIN cells which were plasma deposited at 200 exp 0 to 350 exp 0 were found to have high internal ...

Hydrogen out-diffusion from the n/i interface region plays a major role in controlling the fill factor (FF) and resultant efficiency of n-i-p a-Si:H devices, with the i-layer deposited at high substrate temperatures by the hot wire technique. Modeling cal...

High open-circuit voltage (V{sub oc}) silicon heterojunction (SHJ) solar cells are fabricated in double-heterojunction a-Si:H/c-Si/a-Si:H structures using low temperature (< 225 C) hydrogenated amorphous silicon (a-Si:H) contacts deposited by hot-wire chemical vapor deposition (HWCVD). On p-type c-Si float-zone wafers, we used ...

We propose a nanostructured three-dimensional (nano-3D) solar cell design employing an ultrathin hydrogenated amorphous silicon (a-Si:H) n-i-p junction deposited on zinc oxide (ZnO) nanorod arrays. The ZnO nanorods were prepared by aqueous chemical growth at 80 �C. The photovoltaic performance of the nanorod/a-Si:H solar cell with an ...

Plasma processing of silicon-based materials is widely used in the semiconductor industry for the production integrated circuits. Two very important materials are silicon carbide and silicon nitride. Silicon carbide has found applications in solar cells, flat panel displays, photoreceptors, and photoresist materials, while silicon nitride thin films are ...

Large-area single-junction a-Si:H-based modules have been fabricated with an aperture area conversion efficiency of 10 percent. Triple-junction a-SiC:H/a-Si:H/a-SiGe:H modules with an efficiency of 9 percent have also been demonstrated. The improved large-area performance can be attributed to developments in several areas: (1) the ...

The preparation, properties, and applications of advanced optical materials are discussed in reviews and reports. Sections are devoted to optical switching materials, wavelength-selective surfaces, photovoltaic technology, and solar optical materials. Particular attention is given to the IR properties of electrochromic (EC) materials, the anomalous EC behavior of Ag-WO3 and ...

In Section II, Theoretical Modeling, theories for the capture of electrons by deep centers in hydrogenated amorphous silicon (a-Si:H) and for field-dependent quantum efficiency in a-Si:H are presented. In Section III, Deposition and Doping Studies, the optimization of phosphorus-doped a-Si:H carried out in four different discharge systems is described. ...

to use as an additional coating on active solar absorber surfaces. We have chosen p-i-n a-Si:H solar particles accumulate on the solar cell surface over time, blocking the sunlight and thus reducing the power (Figure 4b) with FIGURE 3. Power conversion of a-Si:H nanodome solar cells. (a) ...

This report describes the research on high-efficiency CdTe-based thin-film solar cells and on high-efficiency a-Si-based thin-film solar cells. Implemented a diode-array spectrograph system and used optical emission spectroscopy to help optimize the reactive sputtering of N-doped ZnTe for CdTe back-contact ...

Voltage of a-Si:H Solar Cells ? a-Si:H cells are low-mobility cells o By definition: slow carrier (hole) drift is the primary limitation to power generation in low-mobility...

... Probing Amorphous Silicon Solar Cells Glass Transparent conducting oxide (SnO2) � 600 nm thick Boron doped (p-type) a-Si � 10 nm thick ...

cell TCO a-Si heterojunction 2-10?m Conducting template Light Trapping benign grain boundary Example Solar Cell Concept <1?m Small ~100nm grains Random crystalline orientation...

Solar cells have been made from hydrogenated amorphous silicon (a- Si:H) films. The films including Si nanoparticles by 3% in the volume fraction have been found to possess good properties. In order to find the method to control this volume fraction, the ...

The interdigitated back contact silicon heterojunction (IBC-SHJ) solar cell requires a low temperature front surface passivation/anti-reflection structure. Conventional silicon surface passivation using SiO2 or a-SiNx is performed at temperature higher than 400°C, which is not suitable for the IBC-SHJ cell. In this paper, we propose a PECVD ...

The interdigitated back contact silicon heterojunction (IBC-SHJ) solar cell requires a low temperature front surface passivation/anti-reflection structure. Conventional silicon surface passivation using SiO2 or a-SiNx is performed at temperature higher than 400�C, which is not suitable for the IBC-SHJ cell. In this paper, we propose a PECVD ...

Hydrogenated, amorphous silicon (a-Si:H) is of great interest for thin film devices used, for example, for the transformation of photon energy and as semiconductor material. Important applications are thin film solar cells, thin film transistors for liqui...

Contents: Surface and Interface Analysis of Semiconductor Devices; Microstructure Analysis of Recording Disks; Analysis of Light-Induced Degradation in Amorphous Silicon (a-Si) Films for Solar Cells; Corrosion Control of Heat Exchangers in Electric Appara...

Best Large-Area, Thin Film Modules (standard conditions, aperture area) |Company|Device|Size (cm2)|Efficiency|Power|Date| |UniSolar|a-Si triple, laminate|21615|6.3%...

A remote silane plasma, capable of depositing solar grade a-Si:H at a rate of 10 nm/s and with an up to ten times higher hole drift mobility than standard a-Si:H, has been investigated by means of several plasma diagnostics. The creation of the different reactive species in the plasma and their contribution to film growth has been ...

This paper identifies the contributions of p�a�SiC:H layers and i�a�Si:H layers to the open circuit voltage of p�i�n type a�Si:H solar cells deposited at a low temperature of 125 �C. We find that poor quality p�a�SiC:H films under regular conditions lead to a restriction of open circuit voltage although the band gap ...

We demonstrate series-connected hybrid tandem multijunction photovoltaics by combining hydrogenated amorphous silicon (a-Si:H) and polymer-based organic photovoltaics (OPVs). To utilize the wide solar spectrum with cost-effective processes, we employed a solution-processed low band gap OPV subcell onto the a-Si:H subcell. The ...

Large-area electronics is mainly concerned with the development of input/output devices such as xerographic drums, page-width image sensors, and addressing circuits for LCD panels and printer heads. The introduction of amorphous hydrogenated silicon (a-Si:H) as a large-area thin-film semiconductor with low-cost fabrication capability has given a new impetus to this field. ...

This report describes work performed to develop improved p-type wide-band-gap hydrogenated amorphous silicon-carbon alloy (a-Si{sub 1-x}C{sub x:}H) thin films and interfaces for the ``top junction`` in hydrogenated amorphous silicon (a-Si:H)-based p-i-n solar cells. We used direct current reactive magnetron sputtering to deposit ...

A series of environmental tests were completed on one type of triple junction a-Si and two types of CuInSe2 thin film solar cells. The environmental tests include electron irradiation at energies of 0.7, 1.0, and 2.0 MeV, proton irradiation at energies of...

of these features makes this a model system for investigating the achievable photo- voltaic efficiency improvements of photovoltaic power. Thin film Si solar cells using hydrogenated amorphous Si a-Si:H and nano- crystalline Si nc-Si:H are among the most well-developed thin film photovoltaic materials, but suffer from low diffu- sion lengths

Results of measurements of the annealing of photodegraded a-Si:H p-i-n solar cells are presented. Although the annealing behavior cannot be described by simple exponential kinetics, it can be characterized by a single activation energy of 1.2 eV. The degradation temperature does not affect this activation energy, although the shape of the annealing curve ...

The scope of the work under this subcontract has involved investigating engineered improvements in the performance and stability of solar cells in a systematic way, which included the following four tasks: (1) Materials research and device development; (2) Process improvement directed by real time diagnostics; (3) Device loss mechanisms; and (4) Characterization strategies for ...

Enormous progress has been made in recent years on a number of photovoltaic (PV) materials and devices in terms of conversion efficiencies. Ultrahigh-efficiency (>30{percent}) PV cells have been fabricated from gallium arsenide (GaAs) and its ternary alloys such as gallium indium phosphide (GaInP{sub 2}). The high-efficiency GaAs-based solar cells ...

In this paper we describe the fabrication of amorphous SiC:H materials and using them as photoelectrodes in photoelectrochemical cells (PEC). With the increase of CH4 flow (in SiH4 gas mixture) during growth, the bandgap, Eg, increases from ~ 1.8eV to ~2.0eV, while the photoconductivity decreases from ~10-5 S/cm to ~10-8 S/cm. These high-quality a-SiC:H materials with Eg of ...

This annual describes the research results of the JPL Flat Plate Solar Photovoltaic Research Project, which is sponsored by the US Department of Energy and is part of the National Photovoltaics Program to initiate a major effort toward the development of cost- competitive solar arrays. Electron cyclotron resonance (ECR) microwave plasma depositions of ...

A multi-layer a-Si:H based thermal neutron detector was designed, fabricated and simulated by Monte Carlo method. The detector consists of two PECVD deposited a-Si:H pin detectors interfaced with coated layers of Gd, as a thermal neutron converter. Simula...

Light trapping in ultrathin plasmonic solar cells Vivian E. Ferry,1,2,* Marc A. Verschuuren,3, and measurement of ultrathin film a-Si:H solar cells with nanostructured plasmonic back contacts, which of optimized, non-random nanostructured back reflectors for thin film solar cells. �2010 Optical Society

We have developed hydrogenated amorphous silicon (a Si:H) back contacts to both p- and n-type silicon wafers, and employed them in double-heterojunction solar cells. These contacts are deposited entirely at low temperature (<250 C) and replace the standard diffused or alloyed back-surface-field contacts used in ...

We present temperature-dependent measurements of I-V curves in the dark and under illumination in order to elucidate the dominant transport mechanisms in amorphous silicon-crystalline silicon (a-Si:H/c-Si) heterojunction solar cells. ZnO:Al/(p)a-Si:H/(n)c-Si/(n+)a-Si:H cells are compared with inversely doped structures and the impact ...

We investigate resistive losses at p-type crystalline Si/hydrogen passivated Si:H/ZnO:Al heterojunction back contacts for high efficiency silicon solar cells. A low tunneling resistance for the (p-type) Si:H/(n-type) ZnO part of the junction requires deposition of Si:H with a high hydrogen dilution rate RH>40 resulting in a highly doped microcrystalline (?c) Si:H layer. ...

We propose a novel hybrid structure for improving the efficiency of thin-film amorphous silicon solar cells. Using ab initio calculations, we demonstrate that nanoporous, amorphous silicon (pa-Si), when filled with polythiophene (PT) inside the pores, forms a staggered gap (type II) heterojunction at the interfaces, where both the highest occupied and the lowest unoccupied ...

The current transport mechanisms in boron-doped amorphous diamond-like carbon (p-a-DLC:H) used as part of the p layer of hydrogenated amorphous silicon (a-Si:H) solar cells are investigated by studying the temperature dependence of the dark current-voltage characteristics of the solar cell. The cell structure is ...

The photoconductance decay (PCD) measurement is a fast and simple method to characterize amorphous/crystalline (a-Si:H/c-Si) silicon interfaces for high-efficiency solar cells. However, PCD only yields information concerning the overall recombination rate in the structure. To overcome this limitation, we have developed and validated a computer-aided PCD ...

The scope of this photoelectrochemical hydrogen research project is defined by multijunction photoelectrode concepts for solar-powered water splitting, with the goal of efficient, stable, and economic operation. From an initial selection of several planar photoelectrode designs, the Hybrid Photoelectrode (HPE) has been identified as the most promising candidate technology. ...

Heterojunction with intrinsic thin layer or ``HIT'' solar cells are considered favorable for large-scale manufacturing of solar modules, as they combine the high efficiency of crystalline silicon (c-Si) solar cells, with the low cost of amorphous silicon technology. In this article, based on experimental data ...

This dissertation provides the first detailed description of the fabrication of flexible, monolithically interconnected photovoltaic sub-modules based on triple-junction amorphous silicon (a-Si) cell technology. There are several problems encountered when progressing from small area (0.25 cm2) solar cells to series interconnected ...

The effect of a thin unhydrogenated amorphous silicon layer (a-Si) on the performance of Si-based MSM photodetector (MSM-PD) was studied. a-Si layer was shown to decrease dark current of Si-based MSM-PD dramatically. a-Si layer was used as barrier enhancement layer in one MSM structure and ...

We report the deposition of improved hydrogenated amorphous silicon germanium (a-SiGe:H) films by the hot wire CVD (HWCVD) technique using a tantalum filament operating at a low temperature. We gauge the material quality of the a-SiGe:H films by comparing infrared, small angle X-ray scattering (SAXS), photocapacitance, and conductivity measurements to earlier results, and ...

Radio frequency glow discharge may be used to deposit films of amorphous silicon from silane gas. It is also possible to dope such films by including traces of diborane or phosphine in the silane gas. Rf sputtering has also been used. This paper intends to study the rectification property of P/undoped a-Si junction. This is particularly important for applications such as a ...

Experimental and theoretical investigations of the growth and properties of doped hydrogenated amorphous silicon (a-Si:H) materials were performed. Controlled doping of laser-induced chemical-vapor-deposited (LICVD) a-Si:H, both n-type and p-type, was ach...

This book contains papers presented at the Twentieth IEEE Photovoltaic Specialists Conference. Some of the topics covered are: Issues and opportunities in space photovoltaics; A novel design for amorphous silicon alloy solar cells; New materials and new analysis method for high efficiency a-Si solar cells; and high efficiency GaAs ...

Dual junction amorphous silicon (a-Si) solar cells produced on polyimide substrate have been selected as the best candidate to produce a lightweight solar array for the PowerSphere program. The PowerSphere concept features a space-inflatable, geodetic sol...

The potential pitfalls which may lead to an overestimation of AM-1 short circuit current densities have been investigated for 0.02 cm/sup 2/ a-SiH /SUB x/ solar cell structures. The authors have spatially profiled carrier collection in a-Si PIN solar cells using a scanned 10..mu.. diameter laser beam. The small beam size yields not ...

This report describes work performed by Pennsylvania State University in collaboration with the NREL Wide-Band-Gap Team. The goal of this team is to develop a single-junction, wide-gap solar cell with good stabilized parameters. The objectives of the subcontract are to (1) develop a cost-effective amorphous silicon PV technology to foster a viable amorphous silicon PV industry ...

Hydrogenated a-Si solar cells were prepared by rf-sputtering. It was found that for a-Si the surface microstructure of sputtered films can be altered by a simple post-deposition etching process and controlled by varying the film preparation conditions. It was demonstrted that such textured surfaces can be advantageous in increasing the efficiency of ...

Photoelectrochemical (PEC) water dissociation into hydrogen and oxygen at a semiconductor-liquid interface offers an environmentally benign approach to hydrogen production. We have developed an integrated PEC device using hydrogenated amorphous silicon carbide (a-SiC or a-SiC:H) material as photoelectrode in conjunction with an amorphous silicon (a-Si) ...

During the past year, approximately 300 large-area (400 cm/sup 2/) PIN hydrogenated amorphous silicon (a-Si:H) solar cells were fabricated and tested. a-Si:H PIN cells which were plasma deposited at 200/sup 0/ to 350/sup 0/ were found to have high internal currents (13mA/cm/sup 2/), whereas those which were deposited by CVD at 500/sup ...

This research was conducted to determine the potential of photochemical vapor deposition (photo-CVD) for producing high-quality, low-band-gap amorphous silicon germanium alloys for use in high-efficiency, multijunction, thin-film photovoltaic solar cells. A photo-CVD reactor for mercury-sensitized photolysis of silane-germane and disilane-germane mixtures was developed. Alloy ...

We have grown device-quality epitaxial silicon thin films at growth rates up to 1.8 μm/min, using hot-wire chemical vapor deposition from silane at substrate temperatures below 750 degrees C. At these rates, which are more than 30 times faster than those used by the amorphous and nanocrystalline Si industry, capital costs for large-scale solar cell production would be ...

The initial task was to develop a flexible glow discharge apparatus capable of yielding reproducible uniform films of a-Si(H) to provide a reference material for comparison with subsequent alloyed materials. Following the completion of this task, C substituted and Ge substituted a-Si/sub x/M/sub 1-x/(H) alloys were prepared over a range of compositions and on a variety of ...

This final report describes results achieved under a 20-month NREL subcontract to develop and understand thin-film solar cell technology associated to CuInSe{sub 2} and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE's long-range efficiency, reliability ...

This report describes results achieved during phase I of a four-phase subcontract to develop and understand thin-film solar cell technology associated with CuInSe2 and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE long-range efficiency, reliability, and ...

This report describes results achieved during a three-year subcontract to develop and understand thin-film solar cell technology associated to CuInSe2 and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE long-range efficiency, reliability, and manufacturing cost ...

This report describes the results achieved during Phase I of a three-phase subcontract to develop and understand thin-film solar cell technology associated with CuInSe2 and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE long-range efficiency, reliability, and ...

This report describes results achieved during phase 1 of a three-phase subcontract to develop and understand thin-film solar cell technology associated to CuInSe{sub 2} and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE long-range efficiency, reliability, and ...

Nanowires have unique optical properties and are considered as important building blocks for energy harvesting applications such as solar cells. However, due to their large surface-to-volume ratios, the recombination of charge carriers through surface states reduces the carrier diffusion lengths in nanowires a few orders of magnitude, often resulting in the low efficiency (a ...

We have conducted a series of accelerated exposure test (AET) studies for various crystalline-Si (c-Si) and amorphous-Si (a-Si) cell samples that were encapsulated with different superstrates, pottants, and substrates. Nonuniform browning patterns of ethylene vinyl acetate (EVA) pottants were observed for glass/EVA/glass-encapsulated c-Si cell samples under ...

A new tunnel recombination junction is fabricated for n�i�p type micromorph tandem solar cells. We insert a thin heavily doped hydrogenated amorphous silicon (a-Si:H) p+ recombination layer between the n a-Si:H and the p hydrogenated nanocrystalline silicon (nc-Si:H) layers to improve the performance of the n�i�p tandem ...

We investigate the performance of a single-junction amorphous Si (a-Si) solar cell fabricated with inductively coupled plasma (ICP) deposition technique. The high-density plasma resulting from high dissociation capacity of ICP enables good-quality hydrogenated Si films to be synthesized at low temperatures. High-density ICP also promotes the diffusion of ...

0.07 to 0.5 Torr with the increase in R. Figures 13 and 14 depict the microstructural evolution, i.e., the surface roughness layer thickness versus the bulk layer thickness as...

and valence band 11 so even though the doping efficiency remains high, the net band misalignment can in fact lead to a decrease of V bi and further enhance the p/i interface...

... iodide based flat panel digital mammography system. ... the proposed dual-energy technique can ... CANCER, DIGITAL SYSTEMS, TISSUES(BIOLOGY ...

ABSTRACT: Conductive-probe atomic force microscopy (CP-AFM) measurements reveal the existence of a conductive channel at the interface between p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) as well as at the interface between n-type a-Si:H and p-type c-Si. This is in good agreement with planar conductance measurements ...

Conductive-probe atomic force microscopy (CP-AFM) measurements reveal the existence of a conductive channel at the interface between p-type hydrogenated amorphous silicon ( a-Si:H) and n-type crystalline silicon ( c-Si) as well as at the interface between n-type a-Si:H and p-type c-Si. This is in good agreement with planar conductance measurements that ...

Transport properties are very important for solar cells. The efficiency of solar cells is determined by the competition of carrier collection and recombination. The most important parameter is the carrier mobility-lifetime product. However, methods commonly used for measuring transport parameters require specially designed samples. The results are often ...

A sophisticated light-management is indispensable for silicon thin-film silicon solar cells based on amorphous (a-Si:H) and microcrystalline (?c-Si:H) silicon. The optical properties of thin-film solar cells have a significant influence on the conversion efficiency. The topology of the nano-textured interfaces ...

In this report, an overview of the recent status of photovoltaic (PV) power generation is first presented from the viewpoint of reducing CO2 emission. Next, the Japanese roadmap for the research and development (R&D) of PV power generation and the progress in the development of various solar cells are explained. In addition, the present status and future prospects of ...

This report summarizes Energy Conversion Devices, Inc.`s (ECD) research under this program. ECD researchers explored the deposition of a-Si at high rates using very-high-frequency plasma MHz, and compared these VHF i-layers with radio-frequency (RF) plasma-deposited i-layers. ECD conducted comprehensive research to develop a {mu}c-Si p{sup +} layer using VHF deposition process with the objectives ...

We prototype an alternative n-type monocrystalline silicon (c-Si) solar cell structure that utilizes an n/i-type hydrogenated amorphous silicon (a-Si:H) front hetero-contact and a back p-n junction formed by alloying aluminum (Al) with the n-type Si wafer...

We prototype an alternative n-type monocrystalline silicon (c-Si) solar cell structure that utilizes an n/i-type hydrogenated amorphous silicon (a-Si:H) front hetero-contact and a back p-n junction formed by alloying aluminum (Al) with the n-type Si wafer.

This report describes the project by Energy Conversion Devices, Inc. (ECD) and its American joint venture, United Solar Systems Corp. (United Solar), to develop and commercialize a roll-to-roll triple-junction amorphous silicon alloy PV manufacturing tech...

This paper describes the effect of doping boron atoms to the intrinsic (i-) layer on the stability of metal/n-i-p/ITO amorphous silicon solar cells. The stability is improved as the amount of doped boron atoms increases. We have explained the improvement in cell performance and its stability by the counterdoping of phosphorus with boron on the basis of the photo-induced change ...

This report summarizes the results of recent a-Si:H thin-film photovoltaic (PV) materials research. The work reported here concerned the fabrication of a-Si:H solar cells at high deposition rates using disilane. This task required the construction of a ne...

Current generation in hydrogenated amorphous silicon, a-Si(H), was found to be predominately from the space-charge region. The mobility-lifetime (..mu..tau) products were the order of 5 x 10/sup -10/ cm/sup 2//V for both holes and electrons. It was necessary to consider trapping and recombination of the optically generated carriers in the space charge region to interpret ...

A detailed study of the photoluminescence, photoconductivity, and infrared absorption of discharge-produced a-Si has shown the optimum substrate temperature to be approx. 300 to 350 exp 0 C. The photovoltaic properties of a-Si solar cells are also optimiz...

Energy Conversion Devices, Inc. (ECD) has designed and constructed a 2 Megawatt (mW) manufacturing line that produces triple-junction spectrum-splitting a-Si alloy solar cells in a continuous roll-to-roll process. This manufacturing line has reliably and consistently produced high efficiency solar cells. We have demonstrated the ...

The atomic structure and electronic properties of crystalline silicon/hydrogenated amorphous silicon (c-Si/a-Si:H) interfaces in silicon heterojunction (SHJ) solar cells are investigated by high-resolution transmission electron microscopy, atomic-resolution Z-contrast imaging, and electron energy loss spectroscopy. We find that all high-performance SHJ ...

In this paper we present a method based on artificial neural networks (ANN) and the use of only one amorphous semiconductor detector to predict the wavelength of incident laser. Amorphous semiconductors and especially amorphous hydrogenated silicon, a-Si:H, are now widely used in many electronic devices, such as solar cells, many types ...

The determination of optical parameters, such as absorption and extinction coefficients, refractive index and the bandgap energy, is crucial to understand the behavior and final efficiency of thin film solar cells based on hydrogenated amorphous silicon (a-Si:H). The influence of small variations of the gas flow rates used for the ...

The determination of optical parameters, such as absorption and extinction coefficients, refractive index and the bandgap energy, is crucial to understand the behavior and final efficiency of thin film solar cells based on hydrogenated amorphous silicon (a-Si:H). The influence of small variations of the gas flow rates used for the ...

Presented at the 2001 NCPV Program Review Meeting: High-quality high-deposition-rate (10 angstrom/s) a-SiGe:H alloy solar cells have been made by hot-wire chemical-vapor deposition. High-quality high-deposition-rate (10 {angstrom}/s) amorphous silicon germanium (a-SiGe:H) alloy solar cells have been made by ...

The incorporation of chlorine has a significant effect on the dark conductivity of doped and undoped hydrogenated amorphous silicon (a-Si:H). The dark conductivity of a-Si:H films deposited from dichlorosilane (SiCl{sub 2}H{sub 2}) and SiH{sub 4}, and doped with diborane, increases by as much as a factor of 100 over the usual a-Si:H,B films deposited ...

Polycrystalline Si (pc-Si) thin-film solar cells on glass have long been considered a very promising approach for lowering the cost of photovoltaic (PV) solar electricity. In recent years there have been dramatic advances with this PV technology, and the first commercial modules (CSG Solar) are expected to hit the marketplace in 2006. ...

This report describes work done by the Syracuse University during Phase 1 of this subcontract. Researchers performed work in the following areas: (1) In ``Electroabsorption measurements and built-in potentials in a-Si:H-based solar cells and devices'', researchers obtained an estimate of Vbi = 1.17 V in cells with a-SiGe:H absorber layers ...

This report describes work performed to develop improved p-type wide-band-gap hydrogenated amorphous silicon-carbon alloy (a-Si(sub 1-x)C(sub x:)H) thin films and interfaces for the ''top junction'' in hydrogenated amorphous silicon (a-Si:H)-based p-i-n s...

Two dimensional hydrogenated amorphous silicon (a-Si:H) pixel arrays are good candidates as flat-panel imagers for applications in medical imaging. Various performance characteristics of these imagers are reviewed and compared with currently used equipments. An important component in the a-Si:H imager is the scintillator screen. A new approach for fabrication of high ...

thin-film solar cell types: hydrogenated amorphous silicon a-Si:H p-i-n cells, organic bulk in organic BHJ solar cells,26 and we suspect it, as well as substrate defects, may be involvedUniversality of non-Ohmic shunt leakage in thin-film solar cells S. Dongaonkar,1,a J. D. Servaites

ULTRA-LIGHTWEIGHT AMORPHOUS SILICON SOLAR CELLS DEPOSITED OIN 7.5pn-1 THICK STAINLESS STEEL of Toledo, Toledo, Ohio 43606 ABSTRACT To significantly reduce the solar cell weight and increase its specific power for space application, we deposited a-Si thin film solar cells on ultra-thin stainless steel

The conversion efficiency of amorphous silicon-hydrogen (a-Si:H) solar cells is limited because the minority-carrier collection length is much shorter than the solar absorption length. To overcome this limitation, a novel cell design is proposed utilizing an a-Si:H active layer less than one collection length thick, which is ...

A research program on hydrogenated amorphous silicon (a-Si:H) and the a-Si:H solar cell is described that includes six research tasks: theoretical modeling, deposition and doping studies, experimental methods for the characterization of a-Si:H, formation of solar-cell structures, theoretical and experimental evaluation of ...

We have studied solar water splitting with a composite semiconductor electrode, composed of an n-i-p junction amorphous silicon (a-Si, Eg? 1.7 eV) layer, an indium tin oxide (ITO) layer, and a tungsten trioxide (WO3, Eg 2.8 eV) particulate layer. The n-i-p a-Si layer, which had more accurately a structure of n-type microcrystalline ( ...

Intrinsic a-Si:H thin films, which can have passivation functions on the surface of crystalline Si, were deposited by inductively coupled plasma chemical vapor deposition (ICP-CVD). The properties of the films were investigated at deposition temperatures ranging from 50 to 400 degrees C. The Si--H stretching mode at 2000 cm(-1), which indicates good film quality, was found in ...

The effect of texture on enhancement and losses in photocurrent in a-Si solar cells is explored using PVOPTICS software and measurements on a-Si device structures. The texture angle has a major impact on light trapping and internal reflection. Increasing the angle causes better internal trapping in the i-layer, but also higher SnO2/a-Si reflection losses, ...

This report describes work performed by Syracuse University under this subcontract. Researchers developed a technique based on electroabsorption measurements for obtaining quantitative estimates of the built-in potential Vbi in a-Si:H-based heterostructure solar cells incorporating microcrystalline or a-SiC:H p layers. Using this new ...

We apply a thin luminescent downshifting (LDS) coating to a hydrogenated amorphous Si (a-Si:H) solar cell and study the mechanism of possible current enhancement. The conversion material used in this study converts wavelengths below 400 nm to a narrow line around 615 nm. This material is coated on the front of the glass of the a-Si:H ...

Ion-beam induced hydrogen migration has been studied in triple layer structures, a-Si/a-Si:H/a-Si and SiO2/a-Si:H/SiO2. Nuclear reaction analysis has been used for simultaneous irradiation with MeV ions and measurement of hydrogen distribution in the structures. It has been established that there is no hydrogen loss from SiO2/a-Si:H/SiO2 structures, but an ...

This work reports on the crystallization of amorphous silicon (a-Si) films doped with 1 at. % of nickel. The films, with thicknesses ranging from 10 to 3000 nm, were deposited using the cosputtering method onto crystalline quartz substrates. In order to investigate the crystallization mechanism in detail, a series of undoped a-Si films prepared under the ...

We have found that the back-surface recombination velocity, Sb, of minority carriers in crystalline silicon (c-Si) thin film solar cells can be reduced to less than 103 cm/s when a boron (B)-doped p-type hydrogenated amorphous silicon (a-Si:H) layer is deposited on the back surface of a p-type c-Si substrate at 200�C, while the value of Sb is 106 cm/s ...

The objective of this study is to measure the molecular species that lead to the growth of hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon (..mu..c-Si) photovoltaic (PV) devices from RF discharges. Neutral radicals produce most of the film growth during this PV-device production, and, by implication, radicals primarily determine the device structure and ...

We suggest a model for the Staebler-Wronski degradation of a-Si based solar cells that can account for long-term performance observations of deployed a-Si photovoltaic modules. The model suggests that the stabilization of the Staebler-Wronski degradation does not occur because an equilibrium between light-induced degradation and ...

Monte Carlo simulations of a proposed a-Si:H-based current-integrating gamma camera were performed. The analysis showed that the intrinsic resolution of such a camera was 1 {approximately} 2.5 mm, which is somewhat better than that of a conventional gamma camera, and that the greater blurring, due to the detection of scattered {gamma}-rays, could be reduced considerably by ...

This report documents the results of material development, single- junction solar cell research, and high-efficiency multijunction cell development. High-quality a-Si:Ge:H:F alloys were made with optical band gaps as low as 1.3 eV; high-conductivity microcrystalline p{sup +} and n{sup +} doped alloys were developed with optical band gaps greater than 2 eV. ...

Polycrystalline thin-film materials based on copper indium diselenide (CuInSe2, CIS) and cadmium telluride (CdTe) are promising thin-film solar cells for various power and specialty applications. Impressive results have been obtained in the past few years for both thin-film copper indium gallium diselenide (CIGS) solar cells and ...

The electrical and optical properties of a-Si:H, a-SiGe:H and a-SiC:H films prepared by d.c. glow discharge method have been characterized. High performance p-i-n devices have also been prepared. The relative stability as well as initial properties of these materials was examined as a function of growth rate. Notable solar cells include efficiencies of ...