Effects of substrate temperature on microstructural and photoluminescent properties of nanocrystalline silicon carbide films

Nanocrystalline silicon carbide (nc-SiC) thin films have been grown on silicon (1 0 0) substrates by helicon wave plasma enhanced chemical vapor deposition technique and the photoluminescence of the films has been tuned from yellow to blue by changing the substrate temperatures (Ts). The resulting nc-SiC films show a microstructure of 3C–SiC nanocrystallites embedded in hydrogenated amorphous SiC matrix. Detailed analysis of the infrared absorption reveals that the degree of crystallization of the films increases with the increase of Ts while the content of hydrogen-related bonds in the films is decreased. The photoluminescence spectra of the nc-SiC films are found to be composed of two Gaussian components. As the Ts increases, the component with higher energy shows a growing trend and the corresponding peaks move to high energy side, indicating that the main luminescence mechanism in the films changes from the defect-related carrier recombination to the quantum confinement effect.