Strong blue photoluminescence from as-fabricated amorphous-Si:H∕SiO2 multilayers

Amorphous-Si:H∕SiO2 multilayers were layer-by-layer deposited and in situ plasma oxidized by a plasma-enhanced chemical vapor deposition system. Blue photoluminescence at room temperature was observed from as-fabricated samples without annealing. By controlling the thickness of the amorphous-Si:H sublayer from 4 to 1.5nm, the photoluminescence peak blueshifts from 466 to 437nm. Strong and stable photoluminescence could be observed by the naked eye for all the samples. Based on the analysis of microstructure and absorption spectra, the mechanism of the blue photoluminescence was discussed.