Ultra-thin nanocrystalline n-type silicon oxide front contact layers for rear emitter silicon heterojunction solar cells

摘要

Hydrogenated nanocrystalline silicon oxide (nc-SiOx:H) films have demonstrated a unique combination of low parasitic absorption and high conductivity. Here, we report on the use of n-type nc-SiOx:H as front surface field (FSF) in rear-emitter silicon heterojunction (SHJ) solar cells exhibiting excellent electrical cell parameters Iat a thickness down to only 5 nm. Using a seed layer, we are able to maintain excellent electrical performance (high fill factor (FF) and open circuit voltage (V-OC)), while enhancing layer transparency for maximizing short circuit current (J(SC)). These results, together with the short deposition time (< 100 s), make the (n)nc-SiOx:H FSF attractive for reducing production costs in industrial applications. The best device, with the optimized (n)nc-SiOx:H FSF layer, shows V-OC of 731 mV, FF of 80.6%, J(SC) of 38.3 mA/cm(2) and a power conversion efficiency of 22.6%.