PUB-2013-TDT

Temperature dependent thermoelectric properties of zinc oxide and gallium-doped zinc oxide thin films prepared by Sol-Gel processing

A. Barasheed, S.R. Sarath Kumar, and H.N. Alshareef, “Temperature dependent thermoelectric properties of zinc oxide and gallium-doped zinc oxide thin films prepared by Sol-Gel processing”
J. Mater. Chem. C, 2013,1, 4122-4127​
A. Barasheed, S.R. Sarath Kumar, and H.N. Alshareef
Zinc oxide, Gallium-doped zinc oxide, Sol-Gel processing
2013
In this study, the temperature dependent thermoelectric properties of sol–gel prepared ZnO and 3% Ga-doped ZnO (GZO) thin films have been explored. The power factor of GZO films, as compared to ZnO, is improved by nearly 17% at high temperature. A stabilization anneal, prior to thermoelectric measurements, in a strongly reducing Ar/H2 (95/5) atmosphere at 500 °C was found to effectively stabilize the chemically derived films, practically eliminating hysteresis during thermoelectric measurements. Subtle changes in the thermoelectric properties of stabilized films have been correlated to oxygen vacancies and excitonic levels that are known to exist in ZnO-based thin films. The role of Ga dopants and defects, formed upon annealing, in driving the observed complex temperature dependence of the thermoelectric properties is discussed.