Bonding configurations and photoluminescence of amorphous Si nanoparticles in SiNx films

The Si-in-SiNx:H films were prepared by helicon wave plasma chemical vapor deposition technique with active gas N2/SiH4/H2, and the tuning photoluminescence of the films from red to blue-green is achieved by changing the N2 flow rate. The analysis of Fourier transform infrared spectroscopy and ultraviolet-visible absorption demonstrate that the deposited films have higher hydrogen contents. Increasing of N2 flow rate makes the hydrogen bonding configurations change and the size of amorphous silicon particles decrease, to which corresponds the increase of band gap and also the decrease of the microstructure order. The tuning photoluminescence is mainly related to the quantum confinement of amorphous silicon particles. The broadening of the spectral widths of main photoluminescence and the enhancement of their intensities are obtained for the films deposited with increasing N2 flow rates.