Pulsed laser deposition of nanocrystalline ZnSe:N thin films
We have grown nanocrystalline ZnSe thin films on GaAs(100) substrates by pulsed laser deposition using a KrF excimer laser. Atomic force microscopy shows that the ZnSe thin films grown on GaAs(100) at 10−1 Torr are flat and dense and are composed of crystallites with an average roughness of 1–2 nm. X-ray diffraction results indicate that crystallites of these ZnSe thin films are of (100) crystalline orientation with an average size of about 10–30 nm. X-ray photoelectron spectroscopy indicates that the as-deposited thin films contain 5–7% [N], and nitrogen with N–Zn bondings includes about 40–60% of the total contained nitrogen. Photoluminescence measurements show a donor-to-acceptor pair recombination emission, which reveals the activation of [N] atoms as shallow acceptors in nanocrystalline ZnSe.