A5007865268- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Copper-based nanomaterials and applications
- Semiconductor materials and interfaces
- nanoparticles nucleation surface interactions
- Solid-state spectroscopy and crystallography
- Perovskite Materials and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Optical properties and cooling technologies in crystalline materials
- Electronic and Structural Properties of Oxides
- ZnO doping and properties
- Optical Polarization and Ellipsometry
- Surface and Thin Film Phenomena
- Optical Coatings and Gratings
- Ocular and Laser Science Research
- Spectroscopy and Laser Applications
- X-ray Diffraction in Crystallography
- Advanced Materials Characterization Techniques
- solar cell performance optimization
- Phase-change materials and chalcogenides
- Metallurgical and Alloy Processes
- Block Copolymer Self-Assembly
- Chemical and Physical Properties of Materials
- Advanced Chemical Physics Studies
Helmholtz-Zentrum Berlin für Materialien und Energie
2013-2022
Renewable Energy Systems (United States)
2018
Max Planck Institute for Solid State Research
2016-2017
Sci-Tech Daresbury
2016-2017
International Iberian Nanotechnology Laboratory
2014
In this paper the Sn loss from thin films of material system Cu–Zn–Sn–S and subsystems Cu–Sn–S Sn–S in high vacuum is investigated. A combination situ x-ray diffractometry fluorescence (XRF) at a synchrotron light source allowed identifying phases, which tend to decompose evaporate Sn-containing compound. On basis XRF results quantification during annealing experiments presented. It can be shown that evaporation rate different phases decreases according order SnS→Cu2SnS3→Cu4SnS4→Cu2ZnSnS4....
The gallium gradient in Cu(In,Ga)Se2 (CIGS) layers, which forms during the two industrially relevant deposition routes, sequential and co-evaporation processes, plays a key role device performance of CIGS thin-film modules. In this contribution, we present comprehensive study on formation, nature, consequences gradients solar cells. formation is analyzed real time rapid selenization process by situ X-ray measurements. addition, grading layer grown with an in-line means depth profiling mass...
In polycrystalline semiconductors, grain boundaries are often sites with prevalence for electron-hole recombination and various strategies have been followed to minimize boundary areas. Generally, large grains or epitaxial films can be obtained at high temperatures. However, growth temperatures limit the choice of substrate materials prove elusive semiconductors comprising volatile elements such as kesterite Cu2ZnSnS4. Here we show that this limitation overcome by a transition matrix densely...
The selenization of Cu-Zn-Sn-S nanocrystals is a promising route for the fabrication low-cost thin film solar cells. However, reaction pathway this process not completely understood. Here, evolution phase formation, grain size, and elemental distributions investigated during nanoparticle precursor films by synchrotron-based in situ energy-dispersive X-ray diffraction fluorescence analysis as well ex electron microscopy. are heated closed volume inside vacuum chamber presence selenium vapor...
The present work shows results on elemental distribution analyses in Cu(In,Ga)Se2 thin films for solar cells performed by use of wavelength-dispersive and energy-dispersive X-ray spectrometry (EDX) a scanning electron microscope, EDX transmission photoelectron, angle-dependent soft emission, secondary ion-mass (SIMS), time-of-flight SIMS, sputtered neutral mass, glow-discharge optical emission Auger electron, Rutherford backscattering spectrometry, microscopy, Raman depth profiling, mapping,...
Abstract Photo‐ and charge‐carrier‐induced ion migration is a major challenge when utilizing metal halide perovskite semiconductors for optoelectronic applications. For mixed iodide/bromide perovskites, the compositional instability due to light‐ or electrical bias induced phase‐segregation restricts exploitation of entire bandgap range. Previous experimental theoretical work suggests that excited states charge carriers trigger process, but exact mechanism still under debate. To identify...
The selenization of metallic Cu–Zn–Sn–Ge precursors is a promising route for the fabrication low-cost and efficient kesterite thin-film solar cells. Nowadays, efficiencies cells are still below 13%. For Cu(In,Ga)Se2 cells, formation compositional gradients along depth absorber layer has been demonstrated to be key requirement producing with conversion above 22% level. No clear understanding reached so far about how produce these in an manner compounds, but among possible candidates, Ge...
Abstract Optical and electrical properties of complex semiconducting alloys like Cu(In,Ga)Se 2 (CIGS) are strongly influenced by the reaction pathways occurring during their deposition process. This makes it desirable to observe control these in real-time deposition. Here we show for first time evolution band gap sub-band-gap defect absorption CIGS thin film as well surface roughness a three-stage co-evaporation process means an optical analysis technique, based on white light reflectometry...
Abstract Starting from stacked binary sulphide precursor layers with copper‐ and zinc‐rich composition the formation of Cu 2 ZnSnS 4 (kesterite) has been investigated. Precursors different layer thicknesses were deposited to evaluate influence material transport on reaction kinetics. During annealing experiments kesterite in precursors was monitored by in‐situ energy‐dispersive X‐ray diffraction. An evaluation rates revealed that at a temperature 500 °C film μm thickness can be formed within...
ABSTRACT In this letter, we report externally confirmed total area efficiencies reaching up to 12.9% for CdS/Cu(In,Ga)S 2 based solar cells. These are the highest such The absorbers were prepared from sputtered metals subsequently sulfurized using rapid thermal processing in sulfur vapor. Structural, compositional, and electrical properties of one these champion cells presented. correlation between Ga distribution profile cell is discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Abstract Ga segregation at the backside of Cu(In,Ga)Se 2 solar cell absorbers is a commonly observed phenomenon for large variety sequential fabrication processes. Here, we investigate correlation between Se incorporation, phase formation and during fast selenisation Cu–In–Ga precursor films in elemental selenium vapour. incorporation are analysed by real‐time synchrotron‐based X‐ray diffraction fluorescence analysis. Correlations depth distributions gained interrupting process several...
Defects rapidly annihilate near stoichiometric composition.
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 We study the sequential fabrication of Cu(In,Ga)Se 2 (CIGSe) absorber layers by using an atmospheric pressure selenization with a process duration only few minutes and utilization elemental selenium vapor from independent Se sources. This technology could proof to be industrially relevant for thin‐film solar cells. Controlling amount provided during metal precursors is shown effective measure adjust Ga in‐depth distribution. A reduced supply CIGSe formation leads more homogeneous...
Responding to a growing interest from the materials science community for residual stress, texture, and microstructure analysis, strong efforts are made enhance existing develop novel methods that allow fast in-situ studies at elevated temperature, measurements under external load, or strain, stress scanning with high spatial resolution. In paper, energy-dispersive diffraction using high-energy white synchrotron radiation is shown provide some distinct advantages concerning texture which...
The growth mechanism of Cu2ZnSnS4 thin films is studied starting from highly textured ZnS precursor films. These precursors were converted to by subsequent deposition Cu, Sn, and S at high temperatures. Orientation measurements revealed that the ⟨111⟩ texture inherited layer. On basis transmission electron microscopy measurements, a model proposed. According this model, initial formation nuclei controlled topotactic or epitactic with respect precursor. further grains appears be independent lattice.
The heating and cooling phase diagram of CsPb(Br x I 1− ) 3 is determined by combinatorial synthesis high throughput X-ray characterization.
While presence of Na is essential for the performance high-efficiency Cu(In,Ga)Se2 thin film solar cells, reasons why addition by post-deposition treatment superior to pre-deposition supply—particularly at low growth temperatures—are not yet fully understood. Here, we show X-ray diffraction and electron microscopy that impedes annihilation stacking faults during Cu-poor/Cu-rich transition temperature 3-stage co-evaporation prevents Cu homogeneity on a microscopic level. Lower charge carrier...
In polycrystalline compound semiconductor thin films, structural defects such as grain boundaries well lateral stress can form during film growth, which may deteriorate their electronic performance and mechanical stability. Cu-based chalcogenide semiconductors $\mathrm{Cu}(\mathrm{In},\mathrm{Ga}){\mathrm{Se}}_{2}$ or ${\mathrm{Cu}}_{2}\mathrm{ZnSn}{(\mathrm{S},\mathrm{Se})}_{4}$, temporary Cu excess growth leads to improved microstructure a reduced boundary density, strategy that has been...