A Systematic Study of the Thermoelectric Properties of GaN-based Wide Band Gap Semiconductors

摘要

In this paper the thermoelectric properties-the Seebeck coefficient, the electrical conductivity and the power factor - of GaN and InGaN thin films grown by Metal Organic Vapor Deposition (MOCVD) are reported. The Seebeck coefficient and power factor of InGaN decreases with increasing indium content, although the electrical conductivity shows an inverse behavior. P-type doped samples demonstrated the highest Seebeck coefficient (637 μV/K in GaN:Mg, 1200 μV/K in InGaN:Mg) but the lowest power factor (01×10~(-4) W/m-K for GaN:Mg, 0.4×10~(-4)W/m-K for InGaN:Mg). The Seebeck coefficient of the doped GaN thin films decreased linearly with log of the carrier concentration. GaN:Si exhibited a maximum power factor of 9.1×10~(-4) W/m-K with a carrier concentration of 1.6×10~(18) cm~(-3), and In_(0.1)Ga_(0.9)N exhibited a maximum power factor of 109×l0~(-4) W/m-K with a carrier concentration of 1.2×10~(18) cm~(-3). The results also indicate that GaN and InGaN-based materials could potentially be useful materials for TE applications at high temperatures.