Passivating contacts for silicon solar cells with 800 °C stability based on tunnel-oxide and highly crystalline thin silicon layer

摘要

Passivating contacts based on nanostructured highly crystalline thin silicon layers are presented. The contact layer stack is optimized towards full crystallinity targeting high transparency. We present an optimization of an electron selective contact and demonstrate excellent surface passivation on n-type and also p-type wafers with such highly crystalline layers. On n-type wafers, the electron selective contact attains an implied open-circuit voltage of 718 mV at an annealing temperature of 925°C. For p-type wafers we find optimum conditions between 850°C and 900°C attaining an implied open-circuit voltage of 723 mV. First tests with hole-selective contacts have yielded an implied open-circuit voltage of up to 676 mV after thermal annealing at 800°C.