Existence of a Pb1-like defect center in porous silicon

Abstract

We performed a detailed study of electron spin resonance (ESR) spectra of porous silicon (PS) samples at different stages of treatment and with different porosities. In addition to the commonly observed P_b0‐like dangling bond, results of curve fitting to our ESR spectra show that a P_b1‐like center, similar to the P_b1 center observed at the (100) crystalline‐Si/SiO₂ interface, appears in the PS nanostructure. The ratio of the number of P_b1‐like centers to that of P_b0‐like centers is related to the PS porosity. Remote hydrogen plasma processing of the annealed PS does not change the ratio significantly, although the total numbers of P_b0‐like and P_b1‐like centers are reduced and photoluminescence efficiency is improved.