Rapid thermal annealing of ZnO thin films grown by using pulsed laser deposition

Abstract

ZnO thin films were grown on the (0001) sapphire substrates by using the pulsed laser deposition (PLD) technique. After the growth of the ZnO thin film, the rapid thermal annealing was performed at temperatures from 200 degrees C to 1000 degrees C. The effect of the post-annealing process on the structural and the optical properties was investigated by using X-ray diffraction (XRD), photoluminescence (PL) and scanning electron microscopy (SEM) measurements. The structural properties obtained by using XRD and SEM showed that the crystal qualities of the ZnO thin films significantly improved as the annealing temperature was increased. The low-temperature (10 K) PL spectra showed a band gap edge emission at about 3.37 eV. The intensity ratio of the band edge emission to the 3.2 eV emission had its maximum value at an annealing temperature of 1000 degrees C.