Achieving high free electron mobility in ZnO:Al thin films grown by reactive pulsed magnetron sputtering

Abstract

The study is focused on the improvement of the free electron mobility in Al-doped ZnO films grown by reactive pulsed magnetron sputtering. At optimum growth conditions low-absorbing films are obtained with a Hall mobility of 46 cm2 V−1 s−1, a free electron density of 6.0×1020 cm−3, and an electrical resistivity of 2.26×10−4 Ω cm. The relation between the mobility and free electron density for different growth conditions is discussed in terms of ionized impurity scattering, impurity clustering, and grain boundary limited transport.