Electrical, structural and optical properties of ZnO thin films grown by pulsed laser deposition

摘要

We report the influence of oxygen partial pressure (PO2) on the electrical, structural and optical properties of no-stoichiometric ZnO (ZnO1-d) thinfilms grown by Nd:YAG pulsed laser deposition. We note that the electrical resistance of theZnO1-dthinfilms is significantly modified by oxygen pressure; the electrical resistance decreases with the O2pressure in the range of 10 to 40 mTorr and reach a minimum resistance ofr~2.1x10-2W-cm at 30 mTorr increasing again after this pressure. These indicate that the increase/decrease of the electrical resistance is ascribed to the annihilation/formation of the residual donor-type defects in theZnO1-dthinfilms, mainly due at the oxygen pressure. It is suggested that the decrease of the electrical resistance is due to the formation of oxygen vacancies (VO) complex defects. X-ray diffraction shown that the oxygen pressure doesn't affect the main peaks positions which reflect the existence of hexagonal ZnO single phase and five principal peaks (100), (002), (101), (110) and (103) appeared in the films. TheZnO1-dthin films shown an average transmittance of ~85% with optical band gap of average value of ~3.3 eV.