Thermoelectric Properties of a-InGaZnOx

Primarily known as an active layer in thin film transistors, the electrical and thermal properties of a-InGaZnOx indicate promise as a thermoelectric material. In contrast to most phonon-blocking, electron-transmitting thermoelectric materials, a-InGaZnOx is a structurally amorphous material that maintains relatively high electron mobility (10-50 cm2/V-s) and optical transparency. Here we report on the electrical conductivity, thermal conductivity, and Seebeck coefficient of this material as a function of charge carrier concentration. Carrier concentration is modulated through thin film annealing in a reducing ambient. Room temperature thermal conductivity is found to be 0.35 W/m-K with a Seebeck coefficient of approximately 200$\mu $V/K. These data suggest room temperature thermoelectric figures of merit in the range of 0.1-0.3 are achievable with these materials, offering the possibility of transparent thermoelectric energy generation.