Abstract
Fundamental characteristics of visible light emission from porous Si (PS) have been studied. The PS layers have been formed on n-type or p-type nondegenerate single-crystal Si wafers by constant-current anodization in HF solutions in the dark or under illumination. From the experimental data on the relation between photoluminescence (PL) spectra and the anodization parameters, it is shown that illumination during anodization and the electrical properties of Si substrates are important determining factors of PL spectra. Injection-type visible electroluminescence from PS diodes with a solid state contact are also presented.