X-ray diffraction lineshape analysis of pulsed laser deposited ZnO nano-structured thin films

Abstract

In this work, we report on the synthesis of highly textured c-oriented zinc oxide (ZnO) thin films on single crystal c-plane sapphire substrates using pulsed laser deposition (PLD). The growth experiments were performed at different substrate temperatures and oxygen pressures. The crystalline properties and surface morphology of the resulting films were studied using XRD peak analysis, rocking curve measurements, and SEM imaging. By varying deposition pressure and temperature, we observe different surface morphologies of the ZnO thin films, from smooth surfaces to clusters of grains and nanorods. The surface and volume structure of the films were found to be correlated. Within the range of experimental parameters used in this work, a growth temperature of 825 °C and a pressure of 10 mTorr lead to nearly epitaxial ZnO thin films having the largest grain size and the lowest strain perpendicular to the substrate surface i.e. along the growth axes. © 2018 Elsevier B.V.