Homoepitaxial MgxZn1 - xO (0≤x≤0.22) thin films grown by pulsed laser deposition

Homoepitaxial MgZnO thin films were grown from PLD targets with 1, 2, 4, and 10 wt.% MgO content on ZnO-buffered ZnO(001) substrates. The resulting Mg content of the films was determined from the blue-shift of the excitonic peak in low-temperature photoluminescence spectra. With increasing Mg content a considerable increase of film mosaicity was observed from HR-XRD (002) rocking curves. Triple-axis reciprocal space maps of symmetric (002) and asymmetric (104) reflections show the structural development in terms of tilt and perpendicular and parallel strain. For more than 1% Mg the films exhibit increasing tensile out-of-plane strain. Very high electron mobilities of 200 cm(2)/Vs at 300 K and 900 cm(2)/Vs at 65 K were measured in the homoepitaxial MgZnO/ZnO thin films with free electron concentrations around 10(18) and 10(17) cm(-3), respectively. The homoepitaxial ZnO template film deposited from a melt-grown ZnO single crystal as PLD target shows two orders of magnitude lower carrier concentration due to high compensation. (C) 2009 Elsevier B.V. All rights reserved,