Impact of Nickel Silicide Rear Metallization on the Series Resistance of Crystalline Silicon Solar Cells

Abstract

The silicon-based solar cell is one of the most important enablers toward high-efficiency, low-cost clean energy resources. Metallization of silicon-based solar cells typically utilizes screen-printed silver–aluminum (Ag–Al), which improves the cells′ electrical performance. To date, metal silicide-based ohmic contacts are occasionally used as an alternative candidate only to the front-contact grid lines in crystalline silicon (c-Si)-based solar cells. In this study, we investigate the electrical characteristics of nickel mono-silicide (NiSi)/Cu–Al ohmic contact on the rear side of c-Si solar cells. We observe a significant enhancement in the fill factor of approximately 6.5 % for NiSi/Cu–Al rear contacts, thereby leading to an increase in the efficiency by 1.2 % compared to Ag–Al. This is attributed to the improvement of the parasitic resistance in which the series resistance decreased by 0.737 Ω cm−2. Further, we complement experimental observation with a simulation of different contact resistance values, which shows the NiSi/Cu–Al rear contact to be a promising low-cost metallization for c-Si solar cells with enhanced efficiency.