Planar light-emitting microcavities based on hydrogenated amorphous silicon carbide

Abstract

The plasma-enhanced chemical vapor deposition (PECVD) method is used to fabricate planar Fabry-Perot microcavities (MCs) with an active region emitting light at the boundary between the visible and infrared (IR) spectral ranges. The MCs comprise an α-Si1 − x C x :H active layer with an increased carbon content and distributed Bragg reflectors (DBRs) constituted by alternating nonemitting α-Si1 − x C x :H/α-SiO2 layers. The active layer and the DBRs are grown in a single technological cycle. Owing to the high optical contrast and low absorption of the layers constituting the DBRs, a high Q factor of the microcavities (Q = 316) and high emission directivity from the MCs for three pairs of layers in the DBRs are achieved. The intensity of the room-temperature photoluminescence exceeds by two orders of magnitude the emission intensity of an identical α-Si1 − x C x :H layer without DBRs. Comparison of the experimental transmittance spectra and those calculated by the transfer-matrix method with consideration for dispersion of the real and imaginary parts of the refractive index of α-Si1 − x C x :H is used to estimate the degree of systematic deviation of the layer thicknesses in the DBRs and to determine the upper limit of the absorption coefficient in α-Si1 − x C x :H layers.