Tunable work function of molybdenum oxynitride for electron-selective contact in crystalline silicon solar cells

Abstract

Dopant-free carrier-selective contacts based on metal compounds have attracted considerable attention for high-efficiency crystalline silicon solar cells. In this work, the feasibility of using molybdenum oxynitride (MoOxNy) as an electron-selective contact layer in n-type crystalline silicon (n-Si) solar cells has been demonstrated. With the increase in the N2:Ar ratio during the sputtering process, the work function of a MoOxNy film decreases from 4.57 to 4.26 eV, which is advantageous for the MoOxNy film to be an electron transport layer. An efficiency of 18.0% has been achieved in n-Si based solar cells using a full-area MoOxNy contact for electron extraction, featuring a high fill factor of 84.6%.