Photoluminescence study of anodized porous Si after HF vapor phase etching

We have studied the mechanism of photoluminescence (PL) shift by hydrofluoric (HF) vapor phase etching in oxygen ambient. Vapor phase etching offers greater efficiency and flexibility, along with reduced damage and contamination for luminescence studies of porous Si. An initial blue shift followed by a red shift was observed in most cases. Transmission Fourier‐transform infrared spectroscopy showed identical bonding environment before and after vapor phase etching, suggesting that the role of surface passivation is irrelevant to the observed PL shift.