On the growth mechanism of pulsed-laser deposited vanadium oxide thin films

The growth of vanadium oxide films with controlled surface structure for optimum-device performance often presents a significant technological problem for theoretical and experimental investigation. In the present investigation, V2O5 thin films were prepared by pulsed-laser deposition (PLD) and were studied for their surface-structure evolution in relation to the growth temperature. The deposition was made onto various substrate materials and in the wide range of substrate temperatures, 30-500degreesC, keeping the oxygen partial pressure at 100mTorr. The films were characterized using atomic force microscopy (AFM) for sample surface imaging in order to understand the effect of substrate temperature and substrate material characteristics on the growth behavior. The results gave a consistent picture of the evolution of vanadium oxide film surface morphology and microstructure in terms of growth, behavior, shape, and distribution of the particles making up films. The grain size, surface texture, and external morphology of V2O5 thin films were found to be highly sensitive to the substrate temperature while the effect of substrate material characteristics is dominant only at higher temperatures. The grain size varied in the range 50-600nm and the surface roughness in the range 9-20 nm with the increasing substrate temperature for crystalline vanadium oxide thin films. The growth mechanism of pulsed-laser deposited vanadium oxide films with oriented structure has been discussed in detail. (C) 2004 Elsevier B.V. All rights reserved.