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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Evaluation of localized vertical current formation in carrier selective passivation layers of silicon solar cells by conductive AFM
摘要: Carrier selective contacts are of growing interest in the development and optimization of high efficiency silicon solar cell concepts. In particular, the passivation mechanism of ultra-thin oxide layers in interaction with poly-Si layers came into focus and the origin of tunnel currents and the so called pinhole conductivity is discussed. Many process parameters and their influence on the passivation effect are not clear, yet. The present study investigates the electrical properties in Si/SiOx/poly-Si layer system from different processes. For this purpose, high-resolution electrical evaluation of the current path density through the interfacial oxide is investigated by conductive AFM using a newly developed image calculation software tool to determine the vertical current path density. We compared two thicknesses of poly-Si (n+ PECVD) layers each at optimum annealing temperature (corresponding to highest i-VOC). The influence of three annealing temperatures (at optimum passivation, below and above) is investigated for an ozone oxide and pinhole densities are analyzed by the TMAH method. Finally, the optimum properties of the layer stack for three interfacial oxides (each at optimum passivation) are studied.
关键词: silicon solar cells,pinhole conductivity,passivation layers,carrier selective contacts,conductive AFM
更新于2025-09-16 10:30:52
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Nanoscale oxygen ion dynamics in SrFeO <sub/>2.5+δ</sub> epitaxial thin films
摘要: A variety of functional properties in transition metal oxides are often underpinned by oxygen vacancies. While the oxygen vacancy concentration and arrangements are well-known to have strong influence on the physical properties of oxides, the oxygen dynamics in oxides—including oxygen ion incorporation and movements during redox reactions—remain elusive. Performing conductive AFM studies of epitaxial thin films of oxygen-deficient SrFeO2.5 treated by air-annealing at various temperatures, we observe oxidation-induced enhancement of local electronic conduction on the higher terraces near the outer step edges at which oxygen ions are preferably incorporated and diffuse into the films. We also show that the local conduction can be reversibly controlled by electric-field-induced redox reactions at room temperature. These results highlight the importance of the nanoscale oxygen dynamics in redox reactions in SrFeO2.5 films.
关键词: SrFeO2.5,transition metal oxides,redox reactions,conductive AFM,oxygen vacancies
更新于2025-09-09 09:28:46