The role of N_x–Si–O_y bonding configuration in acquiring strong blue to red photoluminescence from amorphous SiN_xO_y film

Abstract

We report the acquisition of strong blue to red photoluminescence (PL) from a-SiN x O y thin film that was prepared by plasma enhanced chemical vapor deposition at room temperature. By increasing the flow rate ratio (R) of silane (SiH 4 ) to ammonia (NH 3 ), the luminescent peak position can be tunable in the visible range from 440 to 590 nm, and shown to be independent of temperature as revealed by temperature-dependent PL investigation. The Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectra (XPS) were employed to clarify the relationship between the bonding configuration and PL characteristics. Based on the existence of N–Si–O bond arrangement evidenced in FTIR spectra, the deconvolution of the Si 2p peak was carried out to yield five component peaks corresponding to Si–N 4 , N 3 –Si–O, N 2 –Si–O 2 , N–Si–O 3 , and Si–O 4 . The increase of PL intensity is suggested to be closely related to increased concentration of N x –Si–O y bonds. All the results obtained from temperature-dependent PL spectra, FTIR spectra, and XPS spectra disclosed that the light emission from a-SiN x O y film can be originated from recombination via luminescent centers associated with N x –Si–O y bonding configuration, and the redshift of PL peak with the increase of R may arise from integral effect of N x –Si–O y bonding configuration transformation and valence band maximum upward shift.