Abstract
Nanocrystalline ZnO films with preferred c-axis orientation are grown under varying oxygen partial pressure. The crystalline quality decreases at lower oxygen partial pressure whereas the lattice constant increases. The optical band gap is determined to be ~3.27eV from the transmittance data. The ZnO films when subjected to repeat heating and cooling cycles at temperatures below the deposition temperature their properties get modified. Comparison between the diffraction peak position, interplanar spacing, lattice constant, FWHM, grain size, optical band gap and electrical resistivity before and after cyclic heat treatment of the films is done. The sharp absorption edge of the film deposited at higher oxygen pressure shows a small red shift after heat-treatment leading to a change of 0.04eV in the optical band gap. The resistivity of film deposited at higher oxygen partial pressure reduces to half whereas that of deposited at lower pressure reduces to one-fifth after the heat-treatment..
Keywords
Zinc oxide, Oxygen pressure, Nanocrystalline, PLD, Heat-treatment.
Citation
K. C. DUBEY, A. SRIVASTAVA, R. K. SHUKLA, Oxygen pressure and heat treatment effect on nanocrystalline ZnO films grown by pulsed laser deposition, Optoelectronics and Advanced Materials - Rapid Communications, 4, 2, February 2010, pp.169-173 (2010).
Submitted at: Jan. 28, 2010
Accepted at: Feb. 2, 2010