A5042723395- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Semiconductor materials and interfaces
- Copper-based nanomaterials and applications
- Silicon and Solar Cell Technologies
- Phase-change materials and chalcogenides
- nanoparticles nucleation surface interactions
- Electron and X-Ray Spectroscopy Techniques
- Advanced Semiconductor Detectors and Materials
- Perovskite Materials and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Semiconductor Quantum Structures and Devices
- ZnO doping and properties
- Machine Learning in Materials Science
- Thermography and Photoacoustic Techniques
- Advancements in Solid Oxide Fuel Cells
- Advanced Materials Characterization Techniques
- Optical Coatings and Gratings
- Ion-surface interactions and analysis
- solar cell performance optimization
- Thin-Film Transistor Technologies
- Metallurgical and Alloy Processes
- Advanced Thermodynamics and Statistical Mechanics
- Surface and Thin Film Phenomena
- Heusler alloys: electronic and magnetic properties
Helmholtz-Zentrum Berlin für Materialien und Energie
2009-2019
Physikalisch-Technische Bundesanstalt
2014
Technische Universität Berlin
2002-2010
ABSTRACT In order to transfer the potential for high efficiencies seen Cu(In,Ga)Se 2 (CIGSe) thin films from co‐evaporation processes cheaper large‐scale deposition techniques, a more intricate understanding of CIGSe growth process high‐quality material is required. Hence, mechanism chalcopyrite‐type when varying Cu content during multi‐stage studied. Break‐off experiments help understand intermediate stages thin‐film formation. The film structure and morphology are studied by X‐ray...
In an effort to reduce the complexity and associated production costs of Cu(In,Ga)Se2 (CIGSe)-based solar cells, commonly used sputtered undoped ZnO layer has been modified eliminate requirement for a dedicated buffer layer. After replacing target with mixed ZnO/ZnS target, efficient cells could be prepared by sputtering directly onto as-grown CIGSe surface. This approach now tested high-quality lab-scale glass/Mo/CIGSe substrates. An efficiency 18.3% independently confirmed without any...
Abstract A ZnO nanorod antireflective coating has been prepared on Cu(In,Ga)Se 2 thin film solar cells. This leads to a decrease of the weighted global reflectance cells from 8.6 3.5%. It boosts short‐circuit current up 5.7% without significant effect their open‐circuit voltage and fill factor (FF), which is comparable conventional optimized single layer MgF coating. The was electrochemically an aqueous solution at 80°C. capability arrays (ZNAs) may be further improved by optimization growth...
Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, same performance level as multi-crystalline silicon-wafer technology that dominates commercial PV market. Chalcopyrite heterostructures consist of a layer stack with variety interfaces between different materials. It is chalcopyrite/buffer region (forming p-n junction), which crucial importance...
Abstract Thin film solar cells based on co‐evaporated Cu(In,Ga)Se 2 absorber films present the highest efficiencies among current polycrystalline thin‐film technologies. Thanks to development of a novel experimental setup for in situ growth studies, it was possible follow formation crystalline phases during such deposition processes first time. This synchrotron‐based energy‐dispersive X‐ray diffraction and fluorescence is suited real‐time studies thin vapor processes. Focusing CuInSe CuGaSe...
Abstract Raman microspectroscopy provides the means to obtain local orientations on polycrystalline materials at submicrometer level. The present work demonstrates how orientation-distribution maps composed of intensity distributions can be acquired large areas several hundreds square micrometers. A CuInSe 2 thin film was used as a model system. orientation are evidenced by corresponding measurements using electron backscatter diffraction (EBSD) same identical specimen positions....
The symmetry-dependence of electronic grain boundary (GB) properties in polycrystalline CuInSe2 thin films was investigated a combined study applying scanning electron microscopy, backscatter diffraction, and Kelvin probe force microscopy. We find that highly symmetric Σ3 GBs have higher probability to be charge neutral than lower non-Σ3 GBs. This can help explain the large variations found for Cu(In,Ga)Se2.
The present work reports on investigations of the influence microstructure electronic properties Cu(In,Ga)Se2 (CIGSe) thin-film solar cells. For this purpose, ZnO/CdS/CIGSe stacks these cells were lifted off Mo-coated glass substrates. exposed CIGSe backsides investigated by means electron-beam-induced current (EBIC) and cathodoluminescence (CL) measurements as well electron backscattered diffraction (EBSD). EBIC CL profiles across grain boundaries (GBs), which identified EBSD, do not show...
Abstract In an effort to eliminate the standard CdS buffer layer from chalcopyrite‐based thin film solar cells we have investigated sputtered Zn(O,S) films. They were prepared by partially reactive sputtering a ZnS target in argon/oxygen mixture. Single phase, polycrystalline films achieved for substrate temperatures of at least 100 °C. Test devices completely dry process showed superior blue response and active area conversion efficiencies up 13.7%. (© 2010 WILEY‐VCH Verlag GmbH & Co....
Thin-film solar cells based on Cu(In,Ga)Se2 (CIGSe) reach high power-conversion efficiencies in spite of large dislocation densities up to 1010–1011 cm−2. The present work gives insight into the structural and compositional properties dislocations CIGSe thin films, which are embedded a complete cell stack. These related average electrical potential distributions obtained by means inline electron holography. At part studied, electrostatic shows local minima, all with depths about −1.4 V....
Cu(In,Ga)Se <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$_2$</tex></formula> (CIGSe) absorber layers used in thin-film solar cells exhibit, when grown a multistage process, compositional gradients of Ga and In. In this study, the correlations between gradient microstructure are studied by means transmission electron microscopy (TEM) imaging combined with energy-dispersive X-ray spectroscopy (EDX),...
In a correlative study applying electron backscatter diffraction as well spatially and spectrally resolved cathodoluminescence spectroscopy at low temperatures of about 5 K, the symmetry-dependent optoelectronic properties grain boundaries in Cu(In,Ga)Se2 thin films have been investigated. We find that with lower symmetries tend to show distinct spectral red shift 10 meV weak influence on emission intensity. These behaviors are not detected high-symmetry Σ3 boundaries, or least strongly...
An efficient tandem solar cell requires a top which is highly transparent below the energy gap of its absorber. Previously we had reported on theoretically optimized CuGaSe2 stack based realistic material properties. It promised significant increase in optical transparency and, consequently, enhanced CuGaSe2/Cu(In,Ga)Se2 efficiency. Here present first steps taken towards experimental realization this tandem. We started with mechanically stacked device achieved 8.5% Optical measurements...