High temperature thermoelectric properties of optimized InGaN

Abstract

The effects of carrier concentration, composition, and temperature on the thermoelectric properties of high quality n-type InGaN grown by metal organic chemical vapor deposition (MOCVD) were systematically investigated. The Seebeck coefficient was found to decrease and electrical conductivity increase with increasing carrier concentration, while both were found to decrease with increasing indium composition. Additionally, thermal conductivity was found to decrease by over an order of magnitude as indium composition was increased from 0 to 19%. These trends resulted in optimum carrier concentration and indium composition of 1.1×1019 cm−3 and 17%, respectively, with a room temperature ZT of 0.04. Increasing temperature resulted in a rapidly increasing ZT, reaching a maximum value of 0.34 at 875 K. This significantly improved ZT demonstrates the potential of InGaN and other III-Nitride materials for high temperature thermoelectric applications.