화학공학소재연구정보센터
Applied Surface Science, Vol.257, No.22, 9578-9582, 2011
Photoluminescence of Si from Si nanocrystal-doped SiO2/Si multilayered sample
A multilayered Si nanocrystal-doped SiO2/Si (or Si-nc:SiO2/Si) sample structure is studied to acquire strong photoluminescence (PL) emission of Si via modulating excess Si concentration. The Si-nc:SiO2 results from SiO thin film after thermal annealing. The total thickness of SiO layer remains 150 nm, and is partitioned equally into a number of sublayers (N = 3, 5, 10, or 30) by Si interlayers. For each N-layered sample, a maximal PL intensity of Si can be obtained via optimizing the thickness of Si interlayer (or d(Si)). This maximal PL intensity varies with N, but the ratio of Si to O is nearly a constant. The brightest sample is found to be that of N = 10 and d(Si) = 1 nm, whose PL intensity is similar to 5 times that of N = 1 without additional Si doping, and similar to 2.5 times that of Si-nc:SiO2 prepared by co-evaporating of SiO and Si at the same optimized ratio of Si to O. Discussions are made based on PL, TEM, EDX and reflectance measurements. (C) 2011 Elsevier B.V. All rights reserved.