First principles study on the thermoelectric properties of GaN nanowires with CN point defects

Abstract

In this paper, the effects of CN point defects on the thermoelectric properties of GaN nanowires (NWs) were investigated by using first principles calculation. It is found that the CN point defects can increase the electronic density of states (DOS) near the Fermi level of GaN NWs. The calculation results indicate that CN point defects are beneficial for improving the power factor (PF) of GaN NWs. In addition, it was found that CN point defects can increase the electrical conductivity of NWs. At the same time, it also has impact on the thermal conductivity and Seebeck coefficient of NWs. CN point defects will increase the electrical conductivity of GaN NWs from 0.41 × 10 14Wm−1k−1s−1 to 1.15 × 10 14Wm−1k−1s−1 at T = 700 K. In addition, it's also found that as the temperature increases, CN will cause the Seebeck coefficient decreased from 0.001 VK−1 to 0.0008 VK−1 when T = 700 K. It’s useful for further understanding the thermoelectric properties of wide bandgap semiconductor materials and improving the performance of thermoelectric devices.

Keywords

• GaN NWs
• Thermoelectric properties
• Point defects
• First principles