The indium doping effects on single crystal ZnO film using low temperature hydrothermal synthesis were investigated. Indium was incorporated into the film by adding indium chloride into the growth solution. From the Hall measurement results, indium dopants significantly increase the electron concentration, making the film heavily n type. However, with higher indium doping content, the crystallinity and surface roughness of the films degraded and the carrier mobility decreased due to the formation of smaller grain size. From the structural and electrical measurement results, the best electrical properties have been obtained for 2 at% indium doped ZnO film. This single-crystal film with high crystal quality exhibits the electron concentration of 3 x 10(19) cm(-3) and mobility of 8 cm(2)V(-1) s(-1). These n type single crystal ZnO films can be considered for light emitting diode applications. (C) 2009 Elsevier B.V. All rights reserved.