Fabry-Perot Interference Characteristics of the Photoluminescence in Nanoclustered SiNx:H Thick Films

Thick films (3 4 μm) of nanoclustered SiNx:H on p-type Si (100) substrates were fabricated by using an rf plasma-enhanced chemical vapor deposition (PECVD) method under flows of hydrogendiluted silane and nitrogen gas. The photoluminescence (PL) of the SiNx:H films at room temperature showed broad emission bands modulated by the Fabry-Perot interference patterns at a wavelength of 400 600 nm. The Fabry-Perot interference characteristics in the visible ranges was discussed in view of the refractive index variations of the interface layers between films and the Si substrates and of the near-air surface layers of the thick films. A consideration of the thick films as Fabry-Perot microcavity structures is quite successful in explaining the modulated PL emission spectra, where the refractive indices of the thick films are observed to be in the range of 1.8 2.5 for SiNx:H films with x = 1.0 1.2. These results suggest that nanoclustered SiNx:H films would be a probable material for further applications such as microcavities, resonators, filters, and gain media over wide ranges of visible wavelengths.