The oriented growth of ZnO films on NaCl substrates by pulsed laser ablation

The structure of ZnO thin films grown by 193-nm pulsed laser ablation (PLA) of a ZnO target in a low background pressure Of O-2 on (001) NaCl substrates was examined using selected-area electron diffraction (SAED) in a transmission electron microscope (TEM). Samples were grown at different substrate temperatures in the range 20-300 degreesC. All samples were polycrystalline with the wurtzite crystal structure. Samples deposited at 20 degreesC had a polar (0002) texture. At higher substrate temperatures oriented growth was observed with diffraction patterns showing four-fold symmetry These patterns can be explained by a combination of (11 (2) over bar0)- and (10 (1) over bar1)-oriented grains, the alignment of which can be rationalised in terms of epitaxy with the surface of the NaCl substrate. (C) 2002 Elsevier Science B.V. All rights reserved.