LUMINESCENCE FROM THERMALLY OXIDIZED POROUS SILICON

Porous silicon produced by means of anodization in an HF-based solution has been oxidized in an N2+O2 gas mixture at 900 or 1000-degrees-C to realize the ideal passivation of a porous Si surface with thermally grown oxide instead of hydrogen termination. Visible photoluminescence at room temperature has been observed for porous Si whose surface is terminated by oxygen. It is shown that the luminescence from the porous silicon is extremely stable under Ar+ laser light (488 nm) irradiation even in air at room temperature. A possible mechanism for the visible light emission is discussed on the basis of the excitation intensity dependence of the luminescence.