Shallow dopants and compensating centers in antimony chalcogenides

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The urgent need for high-efficiency, low-cost solar cells motivates researchers to look for new absorber materials for thin-film photovoltaics. Antimony triselenide (Sb2Se3) and antimony trisulfide (Sb2S3) have attracted immense research interest as new absorber for highly efficient, environmentally friendly, stable, and cost-effective thin-film solar cells. Defects and impurities have a decisive impact on the performance of all semiconductor devices. At present, the physics of defects in Sb2Se3 and Sb2S3 remains unexplored and it is not ambiguously clear which of native defects, impurities, or defect complexes and to what extend introduce charge carriers and act as detrimental trap sites or recombination centers. Our proposal aims at bridging this gap. The central goal of the project in question is to study fundamental properties of shallow dopants and compensating centers in single-crystalline Sb2Se3 and Sb2S3. We will focus on technologically important impurities such as chlorine, oxygen, and hydrogen. Optical and electrical spectroscopy will be employed to get insight into microscopic structure, electrical activity, thermal stability, diffusion mechanisms, evolution kinetics, and formation of complexes between extrinsic dopants and native defects. The project will contribute to a better understanding of defects in Sb2Se3 and Sb2S3 and, thus, support efforts in bringing these materials to a broader technological usage in photovoltaics, photoelectrochemical cells, or other solar-driven applications.