Thermoelectric properties of and devices based on free-standing GaN

Abstract

We have studied the thermoelectric properties of free-standing GaN and fabricated a themoelectric power device using this GaN. The electrical resistivity ρ increased and the Seebeck coefficient α slightly increased with increasing temperature in the range from 373 K to 973 K. The power factor decreased with increasing temperature, and its maximum value was 7.0×10−4W∕mK2 at 373 K. The device showed a maximum output voltage Vop and an output power Pmax of 28 mV and 3.35μW at temperature difference of 153 K, respectively. The Pmax and Vop were functions of the temperature difference (ΔT), namely,Pmax∼(ΔT)n (n=2.14) and Vop∼(ΔT)n (n=1.06).