Effect of chamber pressure on red emission from silicon thin films deposited by means of hot-wire CVD

Nanocrystalline silicon (nc-Si) embedded in amorphous silicon oxide (a-SiO_x) films were prepared by hot wire chemical vapor deposition (HW-CVD), also known as catalytic CVD (Cat-CVD) method. In this study, Tungsten (W) filament material was employed for decomposing the source gases in the reaction chamber. Effect of chamber pressure on the phase transition in silicon oxide (SiO_x) has been studied by using X-Ray diffraction (XRD) and Raman spectroscopy techniques. A relationship between phase transition of thin film and Si-H bonding has been recognized and explained by using Fourier transform infrared (FTIR) spectroscopy. The samples deposited at low substrate temperature of 200°C, has shown photoluminescence spectra in the red region and emission of spectra has been found to be in correlation with the size of nc-Si and/or defects present in the thin film.