ELECTROLUMINESCENCE AND PHOTOLUMINESCENCE IN THIN-FILMS OF POROUS SILICON

A reddish-orange electroluminescence has been observed from layers of porous silicon produced by anodic etching of crystalline plates of n- and p-type Si. This luminescence arises on the positive branch of the current-voltage characteristic. Its intensity increases in proportion to the current through the sample. Photoluminescence spectra of the sa me layers were recorded. The structure and composition of the luminesc ent layers were studied by electron, x-ray, photoelectron, and Auger s pectroscopy. The layers of porous silicon are an inhomogeneous system consisting of crystalline Si near the substrate, which converts into a n oxide with fragments of unoxidized Si near the surface.