Research on surface nano-texturation and wet-chemical passivation of multi-crystalline silicon wafer

Abstract

Surfaces nano-texturing has triggered off much attention for trapping sunlight to improve the efficiency of solar cells. Silicon nanowire (SiNWs) arrays, with excellent antireflection performance, will hopefully improve photoelectric conversion of solar cells, however, the deteriorated effective carrier lifetime seriously limits efficiency enhancement of solar devices. Until now, the effect of SiNWs structure on effective carrier lifetime remains unexplored. Herein, the effects of fabrication parameters on the morphology structure and effective carrier lifetime of textured mc-Si were studied in detail. We also firstly discover that the relationship of SiNWs arrays length and effective carrier lifetime shows the negative exponential relation. Moreover, the effects of ethanolic iodine (I–E) concentration, immersion time, and surface pre-conditioning (with and without native oxide) on surface passivation of SiNWs arrays were investigated. It is found that more effective surface passivation could be achieved for the SiNWs arrays with shorter length. Meanwhile, the HF dipping pretreatment is conducive for SiNWs passivation, and which is attributed to Si–Hx termination with lower dissociation energy.