Photoluminescence properties of hydrogenated amorphous silicon nitride thin films deposited by helicon wave plasma chemical vapor deposition

Abstract

Hydrogenated amorphous silicon nitride (a-SiN x :H) thin films are deposited by helicon wave plasma chemical vapor deposition technique. The structural and photoluminescence properties of these films have been characterized by X-ray photoelectron spectroscopy (XPS), Photoluminescence (PL) and ultraviolet-visible (UV-VIS) spectroscopy. It is shown that the silicon atom bonds exist in the Si-Si and Si-N configurations and the amorphous silicon regions appear separately in the Si-rich a-SiN x films. All the PL spectra of the deposited films manifest itself as several interference peaks superposed on an energy-dependent Gaussian distributed band. The PL and absorption results of the deposited films with different nitrogen content support that the luminescence of the Si-rich a-SiN x :H films is related to the photo-excited carriers radiation process in the separated amorphous silicon potential well region, while the blue shift of PL main peaks and the enlargement of PL intensity with increase nitrogen content are ascribed to the size reduction of amorphous silicon separated regions and the enhancement of confinement effect.