{'fraction_non_alphanumeric': 0.010280373831775701, 'fraction_numerical': 0.002803738317757009, 'mean_word_length': 5.413173652694611, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Optical properties and their depth profiling of Si nanocrystals embedded in SiO2 matrix

In this work, we have developed an approach to determination of optical constants of Si nanocrystals embedded in SiO2 matrix synthesized with Si ion implantation. The approach is based on the effective medium approximation, and appropriate models are developed to simulate the secondary ion mass spectroscopy and spectroscopic ellipsometry measurements on the material system. The energy gap expansion of the Si nanocrystals due to the nanocrystal size effect has been obtained by modeling the optical properties with the single-oscillator model. From the energy gap expansion the nanocrystal size can be also obtained with the phenomenological model based on quantum confinement and the bond contraction model. In addition, a novel approach to quantitative determination of depth profiles of optical constants of Si nanocrystals embedded in SiO2 thin films, which is useful to the applications of light emitting and waveguiding of the nanocrystals, is also developed in this work.