Enhanced ultraviolet photoluminescence from V‐doped ZnO thin films prepared by a sol–gel process

Abstract

AbstractUndoped and vanadium‐doped ZnO thin films were prepared on single‐crystalline p‐type Si(100) substrates by a sol–gel process and further annealed in an oxygen atmosphere. The influence of vanadium doping on the structural, surface morphological and optical properties of ZnO thin films was investigated by X‐ray diffraction, atomic force microscopy and photoluminescence measurements. Both the undoped and V‐doped ZnO thin films were of polycrystalline hexagonal wurtzite structure with (002)‐preferred orientation. The crystallite size and the root‐mean‐square roughness of V‐doped ZnO are smaller than those of undoped ZnO. Vanadium doping could reduce deep level defects of ZnO and thus strengthen ultraviolet (UV) emission. The peak intensity of UV emission increased with increasing annealing temperature above 400 °C. After annealing at 800 °C, the UV emission for the V‐doped ZnO films was largely enhanced, while the visible emission was distinctly weakened. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)