Large Electrical Conductivity and Thermoelectric Power Factor of Pulsed Laser-Deposited Zn_1–xGa_xO Thin Films

Abstract

Developing highly efficient transparent thermoelectric oxide thin films is the key for futuristic devices, including ecofriendly portable and sustainable electronic devices. In this paper, we report a large thermoelectric power factor of pulsed laser-deposited ZnO and Ga-doped ZnO thin films. Nearly a 40-fold enhancement in electrical conductivity from 118 S cm −1 (ZnO) to 5050 S cm −1 (Zn 0.98 Ga 0.02 O) is realized with Ga doping. We show that a thermoelectric power factor as high as ∼2.8 and 2.1 mW m −1 K −2 can be achieved for ZnO and Zn 0.97 Ga 0.03 O thin films, respectively, at temperatures ≥640 K. Our findings suggest that the observed large thermoelectric power factor is a result of enhanced electrical conductivity due to the presence of substantial native oxygen vacancy defects (V O ) in the Zn 1−x Ga x O thin films. Our results may facilitate the realization of highperformance transparent solid-state thin film thermoelectric devices.