Novel field‐effect passivation for nanostructured Si solar cells using interfacial sulfur incorporation

Surface passivation of a nanostructured Si solar cells plays a crucial role in collecting photogenerated carriers by mitigating carrier recombination at surface defect sites. Interface modification by additional sulfur (S) incorporation is proposed to enhance the field-effect passivation performance. Here, we report that simple annealing in a H2S ambient induced additional negative fixed charges at the interface between atomic-layer-deposited Al2O3 and nanostructured Si. Annealing at various temperatures allowed us to control the S concentration and the fixed charge density. The optimized S incorporation at the interface significantly enhanced the negative fixed charge density and the minority carrier lifetime up to ~5.9 × 1012 cm−2 and ~780 μs, respectively. As a result, the internal quantum efficiency was nearly two times higher in the blue response region than that of control cells without S incorporation. Copyright © 2017 John Wiley & Sons, Ltd.