Preparative aspects of luminescent Si material-type Si structures were considered in photoelectrochemical etching of n-type single crystal silicon under various anodization conditions in ethanolic solutions containing aqueous hydrofluoric acid. Current-voltage curves strongly depended on the composition of electrlyte solution and light illumination intensity. The first significant increase in anodic photoelectrochemical current was observed at 3 V and then the anodic current increased exponentially, with the second and third peaks at 4.2 V and 6 V, respectively, in 40 per cent HF/ethanol solutions under UV irradiation. Large anodic photoeelectrochemical current flowed as soon as anodic potential was applied with sufficient w hite light illumination. The SEM micrographs of luminescent silicon material showed nanoporous and microporous silicon layers. The microporous silicon layer was thicnened with the total charge passed in the range of 1.9 to 3.5 Coul/cm~2, but the nanoporous layer remained little changed.
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