Vanadium\nOxide Hole-Selective\nContact for Crystalline\nSilicon Solar Cells

The\nselection of an appropriate thin-film deposition\nprocess is\ncrucial for enhancing the efficiency of crystalline silicon (c-Si)\nsolar cells. In this work, we investigate the development of hole-selective\ncontacts for c-Si solar cells utilizing vanadium oxide (V<sub>2</sub>O<sub><i>x</i></sub>) thin films, deposited via atomic\nlayer deposition (ALD) and thermal evaporation techniques. We systematically\ncompare the passivation and contact performance of V<sub>2</sub>O<sub><i>x</i></sub> films on <i>p</i>-type c-Si substrates,\nfocusing on the influence of different oxygen sources, water and ozone,\nused in the ALD process. Our experimental results reveal that V<sub>2</sub>O<sub><i>x</i></sub> films deposited using ALD with\nwater as the oxygen source exhibit superior passivation and contact\nproperties due to enhanced hydrogen passivation at the c-Si/V<sub>2</sub>O<sub><i>x</i></sub> interface. Furthermore, the\nintroduction of a thin aluminum oxide interfacial layer at the c-Si/V<sub>2</sub>O<sub><i>x</i></sub> interface further improves\npassivation, enabling power conversion efficiencies exceeding 22%.\nThese findings underscore the potential of ALD-deposited V<sub>2</sub>O<sub><i>x</i></sub> films, particularly with water as\nthe oxygen source, as promising candidates for optimizing hole-selective\ncontacts in high-efficiency c-Si solar cells.