Hydrogenated nanocrystalline silicon carbide films synthesized by ECR-CVD and its intense visible photoluminescence at room temperature

Abstract

Hydrogenated nanocrystalline silicon carbide (nc-SiC:H) films, which contain nanosize SiC crystals embedded in a-SiC:H matrix were fabricated by the electron cyclotron resonance chemical vapor deposition (ECR-CVD) technique. It was found that under the deposition conditions of strong hydrogen dilutions and high microwave power, films containing SiC nanocrystallites embedded in an SiC:H amorphous matrix could be obtained, as shown by the use of high resolution transmission electron microscopy. Infrared absorption, Raman scattering and X-ray photoelectron spectroscopy studies have also confirmed the successful fabrication of these nc-SiC:H films. Very strong photoluminescence in the visible range with a peak energy of 2.64 eV could be observed from these films at room temperature. Temporal evolution of the PL at the peak emission energy exhibits a bi-exponential decay process with lifetimes that are in the order of ps and ns. The strong light emission and short PL lifetimes observed strongly suggest that the radiative recombination is a result of direct optical transitions in the SiC nanocrystallites. The results obtained in this study show that these nc-SiC:H films are potentially suitable as active layers in large area flat panel displays.