Paramagnetic center in porous silicon: A dangling bond with C3v symmetry

Abstract
Paramagnetic centers in self‐supporting porous Si films formed by anodization of Si(100) and (111) wafers have been studied by X‐band electron paramagnetic resonance (EPR) at room temperature. The EPR spectra indicate that this center has C3v symmetry, and the angular dependence of the line position is described by a g tensor axially symmetric about a 〈111〉 axis; g=2.0024, g=2.0080 for the (100) film and g=2.0020, g=2.0088 for the (111) film. The small g shift along the 〈111〉 axis indicates that the center is assigned to be a dangling bond localized on a single silicon atom. The results indicate that the surface of as‐anodized porous Si maintains a crystallinity of silicon.