Fabry-Perot a-Si:H/a-SiOx:H microcavities with an erbium-doped a-Si:H active layer

Fabry-Perot microcavities tuned to a wavelength of 1.5 µm have been fabricated by means of plasma-enhanced chemical-vapor deposition on the basis of a-Si:H and a-SiOx:H. Distributed Bragg reflectors (DBRs) and the active layer were grown in a single technological cycle. The half-wave active layer was doped with erbium in the course of growth from a metal-organic compound. The high optical contrast enabled a high microcavity quality factor (Q=355) with only three DBR periods. The intensity of erbium photoluminescence (PL) from the microcavity is two orders of magnitude higher than that of erbium emission from an identical a-Si:H layer without DBR. Transmission, reflection, and PL spectra are analyzed. It is found that the spectral shape of the line of erbium PL (transition 4I13/2 → 4I15/2) from the microcavity virtually coincides with the shape of the resonance peak of its transmission spectrum. Theoretical calculations have been performed providing a comprehensive description of the observed experimental spectra.