Homoepitaxial ZnO Thin Films Fabricated by Using Pulsed-Laser Deposition

ZnO thin films were deposited homoepitaxially by using pulsed-laser deposition on ZnO wafers grown by using the hydrothermal method. The dominant shallow donor level in the nominally undoped thin films is Al-Zn, as suggested by thermal admittance spectroscopy and low temperature photoluminescence measurements. The homoepitaxial ZnO:P thin films axe n-conducting in the as-grown state, which facilitates investigations by Hall effect measurements. The Hall mobility of such ZnO:P thin films is higher than that of heteroepitaxial ZnO thin films and its temperature dependence is similar to that of ZnO single crystals grown by seeded chemical vapor transport.