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...

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 ...

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.

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 ...

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.

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.

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 ...

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; ...

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...

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...

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

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 ...

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 ...

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 ...

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 ...

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, ...

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...

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...

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 (

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 ...

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...

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 ...

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 ...

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 ...

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 ...

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...

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...

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 ...

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 ...

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 ...

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, ...

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...

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 ...

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 ...

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 ...

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...

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, ...

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. ...

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 ...

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 ...

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 ...

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.

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

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...

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...

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 ...

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...

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 ...

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 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 ...

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 ...

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 ...

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...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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...

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 ...

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, 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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 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 ...

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...

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 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...

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...

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 ...

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...

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 ...

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 ...

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 ...

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 ...

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) ...

Three dimensional deep contact amorphous silicon/microcrystalline silicon (a-Si/.mu.c-Si) solar cells which use deep (high aspect ratio) p and n contacts to create high electric fields within the carrier collection volume material of the cell. The deep contacts are fabricated using repetitive pulsed laser doping so ...

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 ...

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:

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 ...

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 ...

We have found that a heterostructure made of a conductive transparent oxide (SnO/sub 2/, ITO, or Pt:SiO/sub 2/) and p-type or n-type or intrinsic a-Si:H shows a substantial potential barrier at the interface. This barrier is important in order to explain the behavior of V/sub oc/ versus doping of the p layer in p-i-n solar cells. The ...

In 1978, the US Department of Energy initiated government sponsored research in amorphous materials and thin film solar cells. The program was subsequently transferred to the Solar Energy Research Institute for program management. The program grew into a major program for the development of high efficiency (10% goal), cost effective ...

The effect of interface roughness on the optical properties of amorphous silicon (a-Si:H) solar cells was investigated using rms roughness measurements and computer modeling. The authors deposited four single junction a-Si:H solar cells on Asahi U type substrate each with a ...

Research progress on amorphous Si:H solar cells is described. Tasks include theoretical modeling, deposition and doping studies, experimental characterization of a-Si:H, formation of solar cell structures, and evaluation of solar cell parameters. A new method for ...

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 ...

The stability of solar cells is a key factor in determining the reliability of photovoltaic modules and is of great interest in the case of solar cells having a new technology which has not yet been fully developed. In particular this question arises with hydrogenated amorphous silicon (a-Si) ...

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 ...

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 ...

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 ...

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 ...

The authors report on the development of helium diluted a-Si:H and a-SiGe:H solar cells with higher deposition rates and better feedstock utilization than devices made with hydrogen dilution. Both the initial and the stabilized efficiencies of the He-diluted single-junction a-Si:H and a-SiGe:H ...

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...

of a-Si vs. a-Si/nc-Si 4. Degradation of nc-Si cells vs. V oc & H-diln. Hydrogen atoms and ions ?Hydrogen atom recombination on surface provides local thermal energy (E-R...

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 ethy...

The preparation of amorphous silicon films and solar cells using SiH{sub 2}Cl{sub 2} source gas and electron cyclotron resonance assisted chemical vapor deposition (ECR-CVD) was investigated. By using buffer layers to protect previously deposited layers improved a-Si:H(Cl) solar cells were ...

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 ...

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 ...

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 ...

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 ...

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 ...

Techniques for fabricating a-Si:H solar cells are suitable for areas of several sq m. However, with increasing area, problems with current collection and electrical shorting escalate. This paper reports the development of two significant, large-area structures. One is a series-connected cell, the monolithic ...

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 ...

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...

The optical behavior of thin film solar cells is calculated using a computer simulation study. The application of this method to Schottky-barrier a-Si:H solar cells with highly reflective back contacts shows that multiple reflections are strong for long wavelength light and can be used to ...

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 ...

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 ...

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, ...

Described is 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 ...

An approach to study the optical behavior of hydrogenated amorphous silicon solar cells with rough interfaces using computer modeling is presented. In this approach the descriptive haze parameters of a light scattering interface are related to the root mean square roughness of the interface. Using this approach we investigated the effect of front window ...

Hydrogenated amorphous silicon carbide (a-SiC:H) film has been widely used as an emitter p layer in solar cells. For the better p layer, wide optical bandgap, and high electrical conductivity should be obtained from the effective method. We prepared the boron-doped a-SiC:H thin films using inductively coupled ...

An ultralight flexible a-Si solar cell has been developed utilizing PES (poly ether sulphone) polymer film substrate which has an excellent flexibility with high optical transparency as well as thermal endurance up to 225 C. A systematic examination has been made on its applicability as a substrate material for a-Si:H ...

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 ...

A theory for the capture of electrons by deep centers in hydrogenated amorphous silicon (a-Si:H) is presented. In the section on deposition and doping studies, some recent results obtained with the rf magnetron deposition system are described. Other results show that additions of Ar to dc or ac SiH/sub 4/, discharges cause the dark conductivity and photoconductivity to ...

In this article we discuss basic aspects of single junction a-SiGe:H p-i-n solar cells by coupling computer simulations with experimental characteristics. We are able to fit the dark illuminated current-voltage characteristics and the spectral response curves of a-SiGe:H p-i-n structures in the initial state, modeling the density of ...

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....

Addition of carbon into p-type "window" layers in hydrogenated amorphous silicon (a-Si:H) solar cells enhances short circuit currents and open circuit voltages by a great deal. However, a-Si:H solar cells with high carbon-doped "window" layers exhibit poor fill factors due ...

Crystallization of hydrogenated amorphous silicon (a-Si:H) films deposited on low-cost substrates shows potential for solar cell applications. Secondary ion mass spectrometry (SIMS) was used to study impurity incorporation, hydrogen evolution, and dopant diffusion during the crystallization process

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%.

The progress made on the fabrication of photodiodes on dc magnetron sputtered a-Si:H films is described. Schottky barriers are being made to evaluate the suitability of this material for solar cell applications. Once consistency in the diode structure is demonstrated, pertinent material properties can be measured and optimized.

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 T...

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 mo...

Using the photomixing technique, the authors systematically studied the transport properties of intrinsic hydrogenated amorphous silicon (a-Si:H) samples that had hydrogen content ranging from over 10% to less than 1% and which were produced by the hot-wi...

nano)- crystalline Si (ncSiH)) are separated via an insulating material (e.g. glass, plastic or SiNx). This allows the use of ultra-thin (~300-1000A) a-SiH solar cell where...

The optical absorption in amorphous silicon (a-Si:H) films has been increased by more than an order of magnitude, at long wavelengths, by deposition of the films on randomly textured substrates. This light trapping phenomenon reduces the effective optical absorption threshold for a film with a given thickness and bandgap and is expected to produce a substantial increase in the ...

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) plasm...

Undoped and doped hydrogenated amorphous silicon carbide has proven to be a promising material for many optoelectronic applications, e.g., window layer of hetero-junction amorphous silicon solar cells. High quality doped a-SiC:H films are required to have...

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 op...

A new technique, using controlled DC voltages in addition to RF voltage, was developed to deposit a-Si:H and a-Si:F,H,O, films. This technique allows the growth of films with uniform morphology and yet avoids ion-induced damage. Reproducible films with hi...

a-Si:H/c-Si heterojunctions in solar cells were investigated by admittance spectroscopy, which is able to observe defects at the a-Si:H/c-Si interface. The reasons for the investigation are stated in chapter 2. Chapter 3 describes the main characteristics...

The device current-voltage (I-V) characteristics of thin film silicon stacked tandem solar modules (HYBRID modules) consisting of a hydrogenated amorphous silicon (a-Si:H) cell and a thin-film microcrystalline silicon solar cell (?c-Si) have been investigated under various spectral irradiance ...

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 ...

The emitter of amorphous/crystalline silicon heterojunction (HJ) solar cells is normally very thin. Consequently, the metal used as a front contact can produce a partial or even total depletion of this layer. As a result, the diffusion potential of the p-n junction deviates from its maximum value. In this paper, they report the results concerning HJ in ...

We investigate a passivation scheme using hydrogenated amorphous silicon suboxide (a-SiOx:H) film for industrial solar cell application. The a-SiOx:H films were deposited using plasma-enhanced chemical vapor deposition (PECVD) by decomposing nitrous oxide, helium and silane at a substrate temperature of around 250 �C. An extensive ...

Hybrid solar cells combine the advantages of organic and inorganic materials. We report on the fabrication and performance of hydrogenated amorphous silicon (a-Si:H)/poly(3-hexylthiophene) (P3HT) and a-Si:H/poly(2-methoxy-5-(2{prime}-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH-PPV) solar cells. ...

The thin-film technology is the most promising technology to achieve a significant cost reduction in solar electricity. Laser scribing is an important step to preserve high efficiency of photovoltaic devices on large areas. The high-repetition-rate laser with the pulse duration of 10 ps was applied in selective ablation of multilayer thin-film a-Si ...

A new a-Si:H film deposition apparatus named ''Interdigital-Vertical-Electrode Deposition Apparatus'' has been developed to achieve a high production throughput of a-Si:H devices. In the IVE apparatus, since vertically positioned several rf electrodes and grounded electrodes are arranged interdigitally, the number of discharging section for ...

This report describes work to develop a state-of-the-art electron cyclotron resonance (ECR) plasma-enhanced chemical vapor deposition (PECVD) system. The objective was to understand the deposition processes of amorphous silicon (a-Si:H) and related alloys, with a best-effort improvement of optoelectronic material properties and best-effort stabilization of ...

This report describes work to develop a state-of-the-art electron cyclotron resonance (ECR) plasma-enhanced chemical vapor deposition (PECVD) system. The objective was to understand the deposition processes of amorphous silicon (a-Si:H) and related alloys, with a best-effort improvement of optoelectronic material properties and best-effort stabilization of ...

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 present results of the third phase of research in 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 undo...

We report our progress toward low-temperature HWCVD epitaxial film silicon solar cells on inexpensive seed layers, with a focus on the junction transport physics exhibited by our devices. Heterojunctions of i/p hydrogenated amorphous Si (a-Si) on our n-type epitaxial crystal Si on n++ Si wafers show space-charge-region recombination, ...

Exciton splitting and carrier transport across the amorphous-silicon/ polymer solar cell interface performance. Hydrogenated amorphous silicon a-Si:H /poly 3-hexylthiophene P3HT and a-Si:H/poly 2-methoxy-5- 2, including GaAs with thiophene derivatives,1 nanorod CdSe with polythiophene,2 Si with polyacetylene3 and Cu-phthalocyanine

The electron-hole recombination has been investigated in reactively sputtered hydrogenated amorphous silicon (a-SiH/sub x/) metal Schottky barrier solar cell structures. We find that electron-hole recombination proceeds through states in the middle of the gap. These states, whose density depends on the degree of hydrogenation, have ...

The deposition of a stack of amorphous (a-Si:H) and microcrystalline (?c-Si:H) tandem thin film silicon solar cells (micromorph) requires at least twice the time used for a single junction a-Si:H cell. However, micromorph devices have a higher potential efficiency, thanks to the broader ...

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 ...

The undoped hydrogenated amorphous silicon (a-Si:H) is well-known to be n/sup -/ type. When this material is used to fabricate nip solar cells in a single chamber system, it tends to be contaminated by the residue dopants remaining from the deposition of the first boron-doped p layer unless adequate precautions are taken. The ...

The consequences of using disilane instead of silane for the glow-discharge deposition of a-Si:H solar cells have been studied. Deposition rates were increased fivefold by the use of disilane. The a-Si:H films have a higher hydrogen content, but otherwise are quite similar to silane produced films and possess the same type of gap states. Chlorosilanes, ...

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 (<250degC) and replace the standard diffused or alloyed back-surface-field contacts used in ...

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 ...

Under the PVMat 2A Program, Energy Conversion Devices, Inc. (ECD) has performed manufacturing technology development work utilizing its proprietary continuous roll-to-roll triple-junction a-Si alloy solar cell production line. Among the accomplishments achieved under this program, ECD demonstrated the production of the ...

Computer simulations are reported of hydrogenated amorphous silicon germanium (a-SiGe:H) layers that make up the graded part of the intrinsic layer near the interfaces of a-SiGe:H solar cells. Therefore the graded part is approached with a staircase bandgap profile, consisting of three layers within which the material properties are ...

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 ...

The authors study exciton splitting at the interface of bilayer hybrid solar cells to better understand the physics controlling organic-inorganic device performance. Hydrogenated amorphous silicon (a-Si:H)/poly(3-hexylthiophene) (P3HT) and a-Si:H/poly(2-methoxy-5-(2{prime}-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH-PPV) ...

The light-induced degradation of high-efficiency a-Si:H solar cells (9--11%) prepared by photo-CVD has been investigated. For these samples, the degradation has been found to vary with i-layer thickness and substrate temperature. The influence of different p/i interface conditions on the degradation has also been examined. The ...

During the past year, three novel large-area (100 cm/sup 2/) a-Si:H solar cells were developed with the following configurations: inverted NIP/SS cells with an improved red response; inverted a-Si:H/a-B:H heterojunction cells with high V/sub oc/; and NIP/metal ...

A boron-doped hydrogenated amorphous diamondlike carbon (a-DLC:H) was prepared using a mercury-sensitized photochemical vapor deposition (photo-CVD) method. The source gases were B{sub 2}H{sub 6} and C{sub 2}H{sub 4}. By increasing the boron doping ratio (B{sub 2}H{sub 6}/C{sub 2}H{sub 4}) from 0 to 12000 ppm, the dark conductivity increased from {approximately}10{sup {minus}9} to ...

A boron-doped hydrogenated amorphous diamondlike carbon (a-DLC:H) was prepared using a mercury-sensitized photochemical vapor deposition (photo-CVD) method. The source gases were B2H6 and C2H4. By increasing the boron doping ratio (B2H6/C2H4) from 0 to 12 000 ppm, the dark conductivity increased from ~10-9 to ~10-7 S/cm. A boron-doped a-DLC:H with an energy band gap of 3.8 eV and a dark ...

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 ...

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 ...

For nearly two decades now hydrogenated amorphous silicon has generated considerable interest for its potential use in various device applications namely, solar cells, electrolithography, large-area electronics etc. The development of efficient and economic solar cells has been on the forefront of this research. ...

We investigate the electronic properties of the top junction in hydrogenated amorphous silicon solar cells. In-situ Kelvin probe method is employed to reveal the contact potential profile of the transparent conductive oxide/p+ a-Si,C:H, and p+ a-Si,C:H/a-Si:H interfaces. The films are deposited by dc reactive ...

In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three ...

Three dimensional deep contact amorphous silicon/microcrystalline silicon (a-Si/{micro}c-Si) solar cells are disclosed which use deep (high aspect ratio) p and n contacts to create high electric fields within the carrier collection volume material of the cell. The deep contacts are fabricated using repetitive ...

This report describes a research program to investigate hydrogenated amorphous silicon-germanium alloys (a-Sil-xGex:H) for solar-cell applications. Specifically, studies were carried out to determine why these low-band-gap alloys exhibit photo-electronic properties inferior to those of hydrogenated amorphous silicon (a-Si:H). Two contributors to this ...

The continuous decay of electron drift mobility in intrinsic a-Si:H and a-SiC:H upon light soaking was investigated by the photomixing technique. The photoconductivity, lifetime and drift mobility in intrinsic hydrogenated amorphous silicon (a-Si:H) and hydrogenated amorphous silicon carbide (a-SiC:H) while light-soaking were ...

Using the photomixing technique, the authors systematically studied the transport properties of intrinsic hydrogenated amorphous silicon (a-Si:H) samples that had hydrogen content ranging from over 10% to less than 1% and which were produced by the hot-wire technique at NREL. They investigated the continuous decay of electron drift mobility in intrinsic ...

Surface passivation has become an essential factor for translating high-efficiency crystalline silicon solar cell concepts into industrial production schemes. In photovoltaics, a widespread method to determine the surface recombination is to measure the effective charge carrier lifetime from the photoconductance of symmetrically passivated silicon wafers ...

A detailed study of the electronic density of states (DOS) in the gap of hydrogenated amorphous silicon (a-Si:H) and related alloys is presented. Three independent DOS measurements are employed: field effect, Schottky diode complex admittance, and space-charge-limited currents (SCLC). Refinements in the method of analysis are presented for each technique, and the derived ...

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 ...

The contribution of the built-in electric field at the junction of an a-Si Schottky-barrier solar cell to the open-circuit voltage is investigated experimentally. The cells are fabricated by depositing a 100-nm-thick layer of n(+) a-Si, a 500-nm-thick layer of undoped a-Si, and a ...

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 ...

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 ...

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 ...

This report describes continuing studies on photoluminescence (PL), electroluminescence (EL), Raman, and nuclear magnetic resonance (NMR) by the University of North Carolina-Chapel Hill during the three years and the extension period. Systematic studies on the transition materials and their solar cells and a review of the photo-induced structural changes ...

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 performance and stability of {ital a}-SiGe:H single junction {ital p}-{ital i}-{ital n} solar cells with interfacial layers at the {ital p}/{ital i} and the {ital i}/{ital n} interfaces are reported. It is found that interfacial layers have a strong influence both on the initial performance as well as on the stability of these ...

This report present results of the third phase of research in 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 system, ...

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 ...