Sputtered tantalum oxynitride electron-selective contact for silicon solar cells

Abstract

Wide bandgap metal compound-based carrier-selective contacts have been intensively investigated for crystalline silicon (c-Si) solar cells. In this work, we develop the electron-selective contact tantalum oxynitride (TaOxNy) deposited via magnetron sputtering. The effect of deposition parameters (N2 concentration, power, and pressure) on the optoelectronic properties of TaOxNy is investigated. The optimized TaOxNy film features a low work function of 4.3 eV, a wide bandgap of 2.8 eV, and a low sheet resistance. The surface passivation and contact resistivity of TaOxNy on c-Si are investigated and optimized, and its electron selectivity is verified on c-Si solar cells featuring a full-area TaOxNy contact.