Polarization electric field effect on cross-plane thermal conductivity of GaN/InxGa1-xN/GaN superlattice (x ≤ 0.3)

Abstract

GaN/InxGa1-xN/GaN superlattice (SL) has electric field at interfaces termed as interfacial polarization electric (IPE) field. In this work, effect of this electric field on cross-plane thermal conductivity (kcp) of the SL is investigated for Indium content x ≤ 0.3. IPE field revises phonon velocity which enhances interfacial scattering and thermal boundary resistance (TBR). This is due to unequal changes in specific heat and phonon velocity which leads to decrease in phonon transmission and more mismatches of acoustic properties of material. This reduces kcp. Room temperature kcp in presence (absence) of IPE field for GaN (10nm)/InxGa1-xN (5nm) SL are 4.652 (5.720) and 4.282 (5.221) Wm−1K−1 respectively, for x=0.1 and 0.3. This work demonstrates that electric field of nitride SL can be utilized to reduce k for optimum thermoelectric power production.