Effect of substrate surface morphology and interface microstructure in ZnO thin films formed on various substrates

ZnO thin films have been grown by radio frequency sputtering on Al, Au, Ni, Cu and glass substrates. Crystallinity of ZnO thin films has been estimated by X-ray diffraction (XRD) and reflected high-energy electron diffraction (RHEED). ZnO/substrates interfaces have been observed by cross-section transmission electron microscopy (TEM). ZnO thin films are classified into two groups depending on the type of substrate. ZnO thin films on glass, Au and Al show good c-axis orientation, but orientation of ZnO thin films on Ni and Cu is rather disordered. Considering the relationship between surface morphology of substrates and crystallinity of ZnO, the orientation of ZnO thin film is disordered, when the substrate surface is rough. Crystallinity of ZnO is greatly influenced by surface morphology as well as substrate crystallinity. (C) 2000 Elsevier Science Ltd. All rights reserved.