OPTICAL-PROPERTIES OF POROUS SILICON

The optical and structural properties of porous Si films produced by e lectrochemical and chemical dissolution of Si have been studied by a v ariety of techniques. Raman scattering and transmission electron micro scopy have shown the samples to contain crystalline Si wires and (or) spherites 3-8 nm in diameter and (or) amorphous Si. The optical absorp tion spectra and the wavelength, temperature, and lifetime dependence of the photoluminescence obtained from most of the samples are entirel y consistent with the quantum confinement of excitons in Si nanostruct ures. Quite different photoluminescence was obtained from other sample s composed only of amorphous Si, and this is attributed to the presenc e of silicon oxyhydride species.