Large Electrical Conductivity and Thermoelectric Power Factor of Pulsed Laser-Deposited Zn<sub>1–<i>x</i></sub>Ga<sub><i>x</i></sub>O Thin Films
Vasudevan Jayaseelan, M. Navaneethan, Senthil Kumar Eswaran
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 high-performance transparent solid-state thin film thermoelectric devices.