A5034934675- Silicon and Solar Cell Technologies
- Thin-Film Transistor Technologies
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor materials and interfaces
- Silicon Nanostructures and Photoluminescence
- Perovskite Materials and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Conducting polymers and applications
- Organic Electronics and Photovoltaics
- Chalcogenide Semiconductor Thin Films
- solar cell performance optimization
- Photovoltaic System Optimization Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Nanowire Synthesis and Applications
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and devices
- Ion-surface interactions and analysis
- Corrosion Behavior and Inhibition
- Advanced Machining and Optimization Techniques
- Analytical Chemistry and Sensors
- Electrodeposition and Electroless Coatings
- Advanced Materials Characterization Techniques
- Advanced MRI Techniques and Applications
- Thermal Radiation and Cooling Technologies
- Solid-state spectroscopy and crystallography
Fraunhofer Institute for Solar Energy Systems
2015-2024
University of Freiburg
2017-2024
Fraunhofer Society
2010-2018
European Synchrotron Radiation Facility
2009
The spatial and size distribution of perovskite crystals their morphology strongly influences the PL emission performance solar cell.
The silicon surface texture significantly affects the current density and efficiency of perovskite/silicon tandem solar cells. However, only a few studies have explored fabricating perovskite on textured effect films because limitations solution processes. Here we produce conformal with dry two-step conversion process that incorporates lead oxide sputtering direct contact methyl ammonium iodide. To separately analyze influence each structure films, patterned texture, high-resolution...
Optimally enhancing the performance of perovskite silicon tandem solar cells comes with accurate identification loss origins in device combination optoelectrical simulations assessing respective efficiency gains to prioritize optimization pathways. Herein, various characterization methods, namely, spectrally resolved photoluminescence (PL), transient‐PL, PL‐based implied open‐circuit voltage (i V OC ) imaging, spectrometric characterization, and Suns‐ measurements are combined quantify...
The local prebreakdown behavior of a damage etched multicrystalline silicon solar cell produced from virgin grade feedstock was characterized. At the position micrometer-scaled sites, which correlate with recombination active defects found along grain boundaries, micro-x-ray fluorescence mappings revealed presence Fe precipitate colonies. These measurements represent direct evidence that transition metal clusters lead to decreased breakdown voltage and cause soft diode breakdown.
In the last fifteen years measurement of spatially resolved carrier lifetime has emerged as a valuable tool for characterization silicon wafers and solar cells. most available methods, spatial resolution is constrained to order several 10 100 μm by diffusion length charge carriers. this paper we introduce contactless quantitative technique determine Shockley–Read–Hall with 1 μm. This based on high injection microphotoluminescence spectroscopy allows analysis microscopic defects such grain...
In this paper, spatially resolved photoluminescence (PL) spectroscopy with various excitation wavelengths is presented as a nondestructive and versatile technique providing access to the individual subcells of multijunction solar cells. This method demonstrated on state-of-the-art monolithic tandem cell composed planar perovskite silicon heterojunction cell. It shown that lateral distribution inhomogeneities can be attributed unambiguously cells related manufacturing process. The approach...
Conventional silicon (Si) wafers are produced by energy‐intensive ingot crystallization which is responsible for a major share of solar cell's carbon footprint. This work explores Si epitaxially grown (EpiWafers) that direct epitaxial deposition trichlorosilane on reusable substrate. approach requires less energy and material hence offers potential reduced cost Solar cells made from EpiWafers usually suffer efficiency losses due to recombination at structural crystal defects associated with...
This contribution analyzes the electrochemical etching of copper in a sodium nitrate electrolyte using in-situ Raman spectroscopy. Experiments were conducted specially designed process chamber at voltages below, at, and above limiting current plateau. Below plateau, peak 1050 cm–1 is detected, which attributed to symmetrical ion. However, line shape changes Detailed analysis indicates presence surface film by ex-situ comparison with solutions. In addition, conductivity pH solutions...
Surface-passivated and surface-unpassivated aluminum-alloyed p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -layers are characterized. By varying the firing conditions thickness of screen-printed aluminum paste, different sheet resistances <i xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:xlink="http://www.w3.org/1999/xlink">sh</sub> -layer were fabricated. The emitter saturation current density J...
Abstract The nanostructured surface – also called black silicon (b‐Si) is a promising texture for solar cells because of its extremely low reflectance combined with recombination obtained atomic layer deposited (ALD) thin films. However, the challenges in keeping excellent optical properties and passivation further processing have not been addressed before. Here we study especially applicability ALD on highly boron doped emitters that present crystalline cells. results show can be passivated...
The amount of incomplete ionization aluminum-doped silicon is measured at room temperature by comparing electrochemical capacitance-voltage measurements with micro Raman spectroscopy. It shown that commonly used parameterizations significantly underestimate the effect in Al doped Si. Based on experimental data, we propose new parameter values for parameterization given Altermatt et al., J. Appl. Phys. 100, 113715 (2006). Using these values, saturation current density J0,p+ Al-alloyed region...
Metals corrupt the performance of silicon solar cells severely. In this paper we investigate recombination activity metal precipitates and present a strong positive correlation between their stress around them, independent type forming precipitate. This fundamental observation suggests that stress, together with size precipitate, has dominant effect on metallic precipitates. We explain enhancing near by piezoresistance silicon.
Micro-Raman (μRS) and micro-photoluminescence spectroscopy (μPLS) are demonstrated as valuable characterization techniques for fundamental research on silicon well technological issues in the photovoltaic production. We measure quantitative carrier recombination lifetime doping density with submicron resolution by μPLS μRS. utilizes diffusion from a point excitation source μRS hole density-dependent Fano resonances of first order Raman peak. This is micro defects multicrystalline silicon. In...
Microscopic laser-doped regions in advanced solar cell concepts are analyzed to determine the doping density and identify damage caused by laser process. For these investigations, microphotoluminescence spectroscopy micro-Raman utilized measure density, internal stress, carrier lifetime with micrometer resolution. This analysis proves high applicability of microspectroscopic techniques for characterization analyzing profile local process laser-induced particularly at edges highly doped regions.
Significant improvements in the experimental setup of Micro-Raman (μRS) and Micro-Photoluminescence-Spectroscopy (μPL) for solar cell characterization are reported. The lateral resolution doping density mapping with μRS is improved to below 200 nm. A highly resolved measurement on an aluminum BSF demonstrates increase resolution. Furthermore, thin silicon layers within same presented. An excitation source low penetration depth used screen out background signal from substrate. Finally, a...
A quantitative doping density mapping technique for silicon samples with micrometer spatial resolution is presented. Being based on confocal microphotoluminescence spectroscopy, the allows detailed analyses concentration of microscopic technological structures in solar cells. The microscope setup enables laser illumination micrometer-sized focus and fast low-noise detection emitted luminescent radiation which depends free excess carrier density. determined by calibrating depth-dependent...
Measuring the excess charge carrier density is a widespread approach to accessing lifetime in silicon using an equation of continuity. In this paper, we investigate scenario spatially non-uniform pulsed or modulated optical excitation and measurement emitted photoluminescence intensity. order ascertain how obtain scenario, rigorous theoretical analysis induced dynamics elaborated. Emanating from intensity-weighted average density, macroscopic continuity which accounts for spatial...
This contribution analyzes the electrochemical etching of copper in a sodium nitrate electrolyte using in-situ Raman spectroscopy. Experiments were conducted specially designed process chamber at voltages below, at, and above limiting current plateau. Below plateau, peak 1050 cm–1 is detected, which attributed to symmetrical ion. However, line shape changes Detailed analysis indicates presence surface film by ex-situ comparison with solutions. In addition, conductivity pH solutions...
Abstract Defect rich regions in multicrystalline silicon are investigated by Raman spectroscopy at high and low injection levels. By analyzing the Fano type asymmetry spectral position of first order peak crucial properties such as recombination lifetime, doping density stress can be extracted simultaneously. Due to small wavelength excitation laser spatial resolution these measurements is significantly below 1 µm, which gives new insight into impact defects on carrier lifetime. The results...
Silicon nanocrystals (Si NCs) embedded in Si-based dielectrics provide a high band gap material (1.7 eV) and enable the construction of all-crystalline Si tandem solar cells. However, nanocrystal formation involves high-temperature annealing which deteriorates properties any previously established selective contacts. The inter-diffusion dopants during alters NC limits built-in voltage. Furthermore, most devices presented so far also involve electrically active bulk therefore do not allow...
The bulk and surface recombination determine the electrical performance of many semiconductor devices. Yet, experimental determination separation both rate remains challenging. This paper presents measurement in silicon by means time resolved photoluminescence spectroscopy. high temporal resolution applied correlated single photon counting technique is exploited to access response a sample upon pulsed excitation nanosecond millisecond regime on sub-cm2 area. A rigorous data fitting algorithm...