White luminescence from silica glass containing red/green/blue luminescent nanocrystalline silicon particles

Abstract

Silica glasses containing blue/green/red luminescent nanocrystalline silicon (nc-Si) particles that consist of monolayer and/or three-layer structures were fabricated by a radio-frequency sputtering technique and postannealing treatment. These silica glasses showed very broad luminescence spectra with a peak at 460 nm (blue light), 550 nm (green light), and 800 nm (red light). When these samples were irradiated by using a xenon lamp with an optical bandpass filter of 313 nm, the luminescence colors from these silica glasses were a white light. The white luminescence of the sample with the three-layer structure exhibited the high luminance value of 1.5 cd/m2. This value was ascribed to the adjustment of sizes and densities of blue/green/red luminescent nc-Si particles, and the lowering of densities of Pb centers (nonradiative recombination centers) at the nc-Si particle/silica glass interface layer.