A5091570717- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Semiconductor materials and interfaces
- Silicon and Solar Cell Technologies
- Copper-based nanomaterials and applications
- Thin-Film Transistor Technologies
- Advanced Semiconductor Detectors and Materials
- ZnO doping and properties
- Semiconductor Quantum Structures and Devices
- Gas Sensing Nanomaterials and Sensors
- Perovskite Materials and Applications
- Silicon Nanostructures and Photoluminescence
- solar cell performance optimization
- nanoparticles nucleation surface interactions
- Optical Coatings and Gratings
- Advanced Electron Microscopy Techniques and Applications
- Analytical Chemistry and Sensors
- Machine Learning in Materials Science
- Electrocatalysts for Energy Conversion
- Photovoltaic System Optimization Techniques
- Transition Metal Oxide Nanomaterials
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and devices
Columbia University
2023
National Renewable Energy Laboratory
1996-2010
Our effort towards the attainment of high performance devices has yielded several with total-area conversion efficiencies above 16%, highest measuring 16.8% under standard reporting conditions (ASTM E892-87, Global 1000 W/m/sup 2/). The first attempts to translate this development larger areas resulted in an efficiency 12.5% for a 16.8-cm/sup 2/ monolithically interconnected submodule test structure, and 15.3% 4.85-cm/sup single cell. Achievement 17.2% device fabricated operation...
In this work, we found that the interdiffusion of CdS and Zn2SnO4 (ZTO) layers can occur either at high temperature (550–650 °C) in Ar or lower (400–420 a CdCl2 atmosphere. By integrating film into CdS/CdTe solar cell as buffer layer, feature solve several critical issues improve device performance reproducibility both SnO2-based Cd2SnO4-based CdTe cells. Interdiffusion consumes from ZTO sides during fabrication process improves quantum efficiency short wavelengths. The acts Zn source to...
We report the results of an extensive study employing numerous methods to characterize carrier transport within copper indium gallium sulfoselenide (CIGSS) photovoltaic devices, whose absorber layers were fabricated by diverse process in multiple laboratories. This collection samples exhibits a wide variation morphologies, compositions, and solar power conversion efficiencies. An characterization properties is reported here—including those derived from capacitance–voltage, admittance...
High-quality DuPont screen-printed Ag contacts were achieved on high sheet-resistance emitters (100 /spl Omega//sq) by rapid alloying of PV168 paste. Excellent specific contact resistance (/spl sim/1 m/spl Omega/-cm/sup 2/) in conjunction with fill factor (FF) (0.775) obtained 100 Omega//sq a 900/spl deg/C spike firing the paste belt furnace. The combination characteristics and optimized single-step low-thermal budget resulted cost-effective manufacturable process for high-efficiency Si...
In this paper, the authors have focused on formation and role of CdS/CdTe interface CdTe solar cells. The devices were made using chemical bath deposited (CBD) CdS SnO/sub 2//glass substrates was by close spaced sublimation (CSS) subsequently CdCl/sub 2/ treated annealed. Compositional analysis showed considerable interdiffusion Te S as well Cl accumulation at interface. Micro-photoluminescence (PL) reveals sulfur grain boundaries a graded CdS/sub x/Te/sub 1-x/ alloy Their leads them to...
In this paper, we have studied the effect of high-resistance SnO2 buffer layers, deposited by low-pressure chemical-vapor deposition, on CdS/CdTe device performance. Our results indicate that when devices a very thin layer CdS or no at all, i-SnO2 helps to increase efficiency. When is thicker than 600 Å, performance dominated thickness, not layer. If be used enhance performance, conclude better needed.
We study the performance of CdS/CdTe thin-film devices contacted with ZnTe:Cu/Ti various thickness at a higher-than-optimum temperature ~360degC. At this temperature, optimum device requires same ZnTe:Cu as for similar contacts formed lower 320degC. C-V analysis indicates that layer <~0.5 mum does not yield degree CdTe net acceptor concentration necessary to reduce space charge width its value n-p operation. The thickest investigated (1mum) yields highest concentration, lowest J <sub...
By varying the argon pressure during deposition, authors have prepared a set of sputtered molybdenum films on soda-lime glass substrates with range mechanical and electrical properties. These were subsequently exposed to several processing steps used in fabrication copper-indium-diselenide (CIS) solar sells. Processing interest include heating vacuum, exposure selenium vapor at elevated temperatures, deposition CIS CIGS layers over Mo. Resulting Mo structures characterized using XPS, SEM,...
Cu diffusion from a ZnTe:Cu/Ti back contact onto CdS/CdTe thin-film solar cells is studied. We find if insufficient, the entire CdTe layer depleted. However, excessive, depletion width can become too narrow to provide optimum current collection. This analysis suggests that most processes used for devices are optimized (often unknowingly) result in extends just far enough into yield highest possible field region where light absorption occurs. Analysis of samples with very high concentration...
Abstract Quantification of microstructures is crucial for understanding processing–structure and structure–property relationships in polycrystalline materials. Delineating grain boundaries bright-field transmission electron micrographs, however, challenging due to complex diffraction contrast images. Conventional edge detection algorithms are inadequate; instead, manual tracing usually required. This study demonstrates the first successful machine learning approach boundary micrographs. The...
The doping-dependent, near-band-edge optical-absorption coefficient α(hν) was deduced from optical transmission measurements in n-type GaAs thin films. selenium-doped films were grown by metalorganic chemical-vapor deposition and doped to produce room-temperature electron concentrations 1.3×1017 3.8×1018 cm−3. covered photon energies between 1.35 1.7 eV performed on double heterostructures with the substrate removed selective etching. results show good qualitative agreement previous studies...
We have studied the effects on cell stability of amount copper in back contact and dependence CdCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> activation treatment for sputtered CdS/CdTe cells. Unencapsulated cells were tested dark at one sun 85°C higher. find that with > 3 nm evaporated Cu (covered 20 Au) had initially higher short-circuit current but less stable than limited (1-3 nm) without intentional neither better nor initial...
CdTe-based thin-film solar cells have been limited to the conventional SnO/sub 2//CdS/CdTe device structure. In this paper, we report a modified structure consisting of Cd/sub 2/SnO/sub 4//Zn/sub x/Cd/sub 1-x/S/CdS/CdTe layers, that yields improved performance and reproducibility. Cadmium stannate (Cd/sub 4/, or CTO) transparent conductive oxide (TCO) films several significant advantages over 2/ films. CTO-based CdTe approximately 1 mA/cm/sup higher J/sub sc/ than 2/-based cells. Integrating...
We have investigated the effect of deposition conditions SnO2 films, deposited by chemical vapor using tin tetrachloride and tetramethyltin precursors, on film properties. The type precursor temperature affect morphology films. structure films is determined temperature: at low temperatures show a mixed SnO phase. processing substrate determine impurity content in Electrical properties (e.g., carrier mobility) optical are affected these layers.
Interaction between chemical bath deposited CdS and ZnO window layers are a focus of this paper. Low temperature anneals were used to follow the changes at interface. Optical absorption spectra show that intermix upon annealing. Heat treatments applied ZnO/CdS/CuInGaSe/sub 2/ thin film solar cells produced in short long wavelength responses. The latter is attributed an increase energy gap absorber by diffusion S, it confirmed SIMS. interdiffusion shown collection, hence current density...
Abstract This paper describes the effect of Cd and Zn impurities in formation photovoltaic junctions using CuInSe 2 ‐based alloy thin‐film absorbers. We compare properties solar cells fabricated by CdS window layers with those obtained or treatment from liquid vapor‐phase environments. Efficient are for latter two cases, their comparable to layers. The results interpreted terms ability produce n‐type doping surface region (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The results of a new application rapid isothermal processing (RIP) for the junction and ohmic contact formation in compound semiconductors are presented this paper. In process, particular semiconductor is selected so that one element acts as dopant other preferably high vapor pressure element. A thin layer deposited by suitable technique on top followed low-temperature (∼300–500 °C) RIP step. Results indium phosphide cadmium telluride representing group III–V II–VI, respectively. Preliminary...