Vanadium Oxide Hole-Selective Contact for Crystalline Silicon Solar Cells

The selection of an appropriate thin-film deposition process is crucial for enhancing the efficiency of crystalline silicon (c-Si) solar cells. In this work, we investigate the development of hole-selective contacts for c-Si solar cells utilizing vanadium oxide (V2Ox) thin films, deposited via atomic layer deposition (ALD) and thermal evaporation techniques. We systematically compare the passivation and contact performance of V2Ox films on p-type c-Si substrates, focusing on the influence of different oxygen sources, water and ozone, used in the ALD process. Our experimental results reveal that V2Ox films deposited using ALD with water as the oxygen source exhibit superior passivation and contact properties due to enhanced hydrogen passivation at the c-Si/V2Ox interface. Furthermore, the introduction of a thin aluminum oxide interfacial layer at the c-Si/V2Ox interface further improves passivation, enabling power conversion efficiencies exceeding 22%. These findings underscore the potential of ALD-deposited V2Ox films, particularly with water as the oxygen source, as promising candidates for optimizing hole-selective contacts in high-efficiency c-Si solar cells.