Preparation and properties of p-type Ag-doped ZnMgO thin films by pulsed laser deposition

We report on p-type Ag-doped ZnMgO thin films prepared on quartz substrates by pulsed laser deposition. The effects of substrate temperature on the structural, electrical and optical properties of the films are investigated in detail. All the films we obtained have a preferred orientation with the c-axis perpendicular to the substrates. Secondary ion mass spectroscopy and X-ray photoelectron spectroscopy measurements confirm that Ag has been incorporated into the films and principally occupies Zn site in the state of Ag+ ion and acts as an acceptor. An acceptable p-type conduction, with a resistivity of 24.96 Omega cm, a Hall mobility of 0.32 cm(2) V-1 s(-1), and a hole concentration of 7.89 x 10(17) cm(-3) at room temperature, was obtained for the film grown at the optimal substrate temperature of 400 degrees C. The formation of good p-type conduction in this film might be due to a combined effect of the increase of substitutional-Ag (Ag-Zn) density and the suppression of the oxygen-related defects. The p-type conduction of Ag-doped ZnMgO film is further confirmed by a rectifying Ag-doped ZnMgO/i-ZnO/Al-doped ZnMgO heterojunction. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.