Modified Photoluminescence by Silicon-Based One-Dimensional Photonic Crystal Microcavities

Photoluminescence (PL) from one-dimensional photonic band structures is investigated. The doped photonic crystal with microcavities are fabricated by using alternating hydrogenated amorphous silicon nitride (a-SiN_x:H/a-SiN_y:H) layers in a plasma enhanced chemical vapour deposition (PECVD) chamber. It is observed that microcavities strongly modify the PL spectra from active hydrogenated amorphous silicon nitride (a-SiN_z:H) thin film. By comparison, the wide emission band width 208nm is strongly narrowed to 11\,nm, and the resonant enhancement of the peak PL intensity is about two orders of magnitude with respect to the emission of the λ/2-thick layer of a-SiN_z:H. A linewidth of Δλ=11nm and a quality factor of Q=69 are achieved in our one-dimensional a-SiN_z photonic crystal microcavities. Measurements of transmittance spectra of the as-grown samples show that the transmittance resonant peak of a cavity mode at 710nm is introduced into the band gap of one-dimensional photonic crystal distributed Bragg reflector (DBR), which further verifies the microcavity effects.