Correlation between light emission and dangling bonds in porous silicon

The results of a correlated study of light emmision and dangling bonds in porous silicon (PS) are given using electron spin resonance (ESR), photoluminescence (PL) and Fourier transform infrared (FTIR) transmission measurements. ESR analysis revealed the presence of two kinds of paramagnetic defect centers, which are (1) the a-center, namely Si dangling bonds with an isotropic g-value of 2.0055 in amorphous states, and (2) the Pb center, namely · SiSi3 defects at the SiSiO2 interface. These paramagnetic defect centers closely relate to non-radiative emission centers (recombination killer centers). Crystallinity and PL intensity of PS are increased by increasing the anodization temperature.