摘要
The amorphous silicon nanoparticles （Si NPs） embedded in silicon nitride （SiNx） films prepared by helicon wave plasma-enhanced chemical vapor deposition （HWP-CVD） technique are studied. From Raman scattering investigation, we determine that the deposited film has the structure of silicon nanocrystals embedded in silicon nitride （nc-Si/SiNx） thin film at a certain hydrogen dilution amount. The analysis of optical absorption spectra implies that the Si NPs is affected by quantum size effects and has the nature of an indirect-band-gap semiconductor. Further, considering the effects of the mean Si NP size and their dispersion on oscillator strength, and quantum-confinement, we obtain an analytical expression for the spectral absorbance of ensemble samples. Gaussian as well as lognormal size-distributions of the Si NPs are considered for optical absorption coefficient calculations. The influence of the particle size-distribution on the optical absorption spectra was systematically studied. We present the fitting of the optical absorption experimental data with our model and discuss the results.
基金
Supported by the National Natural Science Foundation of China under Grant No.60940020
the Natural Foundation of Hebei Province under Grant No.E2008000619
