Properties of phosphorus-doped zinc oxide films grown by pulsed laser deposition

Electrical and chemical bonding properties of P-doped ZnO thin films grown by pulsed laser deposition on sapphire substrates were systematically characterized utilizing the Hall effect and x-ray photoelectron spectroscopy (XPS) measurements. Oxygen growth pressure and postannealing processing play a great role in the properties of these films. Increasing oxygen growth pressure from 5 to 20 Pa enhanced the resistivity of P-doped ZnO films by three orders of magnitude. P-doped ZnO films grown at 700 degrees C under 20 Pa O(2) exhibited p-type conductivity with hole concentration of 5 x 10(17) cm(-3) and hole mobility of 0.3 cm(2)/V s. Rapid thermal annealing processing decreased the electron density in the P-doped ZnO films. XPS binding energies of P 2s and 2p peaks showed formation of P-O bonds which increased with oxygen pressure in the films. This indicates formation of defect complexes of P dopants occupying zinc sites P(Zn) and zinc vacancies V(Zn) in the P-doped ZnO films. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3554838]