INVESTIGATION OF SILICON-HYDRIDE NANODOTPROPERTIES USING DENSITY FUNCTIONAL THEORY

Abstract

The work aims to elucidate the optical and structural properties of silicon hydride nanoclusters and its bulk via density functional calculations. The molecular geometry is fully optimized with the help of DFT method using Gaussian 09 and Gaussian View 05 Software. Bandgaps are calculated using two approaches; first one using HOMO-LUMO concept and the second one is extracted from UV-vis spectrum. The calculated bandgap of silicon hydride is 3.7 eV. XRD data has also been analyzed using VESTA software, which shows the presence of a silicon matrix that contains organized silicon clusters forming an amorphous silicon matrix. A comprehensive investigation of amorphous films by X-ray diffraction (XRD) shows that the strongest peak in XRD patterns occurs at approximately 30.95°. Using XRD data, average size of optimized silicon hydride nano-cluster has been found to be 158.5 nm. Apparently large value of the cluster size can be attributed to the partially amorphous nature of silicon hydride nanocluster. The partial amorphous nature of silicon hydride is further confirmed from the analysis of its Raman spectrum. An overestimation of size in this case is not ruled out. Raman spectrum is calculated to further confirm deviations in nano-crystalline behavior. We also investigate and reveal properties using IR-spectrum, UV-vis-spectrum, NMR spectrum, and HOMO-LUMO gap.