VARIATION OF PHOTOLUMINESCENCE PROPERTIES OF STAIN-ETCHED SI WITH CRYSTALLINITY OF STARTING POLYCRYSTALLINE SI FILMS

We have studied the relationship between the photoluminescence property and crystallinity of stain-etched polycrystalline Si (poly-Si) films. Poly-Si films having different crystallite size were prepared on SiO2 by electron beam evaporation of amorphous Si with subsequent annealing in the temperature range of 600-900-degrees-C. Porous Si layers were formed by stain etching of these poly-Si films. It has been found that the size of nanocrystallites in the porous Si layer is independent of the crystallite size of poly-Si and appears to be almost a constant value (about 5 nm). However, the photoluminescence peak wavelength became shorter as the crystallite size in the poly-Si films before stain-etching was increased, and the photoluminescence intensity became stronger as the density of crystallites in stain-etched poly-Si films was increased.