Role of interfacial electric field on thermal conductivity of In x Al1−x N/GaN superlattice (x = 0.17)

Abstract

Abstract In this paper, we report the role of the interfacial polarization electrical field in thermal conductivity of In x Al1−x N/GaN superlattice. Thermal conductivity reduction is one recent effort to improve thermoelectric device efficiency because a small reduction in thermal conductivity can enhance the figure of merit significantly. Quantum size effect and thermal boundary resistance are responsible for this reduction. The theoretical results demonstrate that the interfacial polarization electric field modifies acoustic phonon properties through elastic moduli and phonon group velocity as a result of the inverse piezoelectric effect. This enhances phonon scattering and thermal boundary resistance. Consequently, the thermal conductivity of the superlattice is reduced. Room temperature thermal conductivity is found to be 2.94 (3.35) W m−1 K−1 for In x Al1−x N/GaN superlattice (x = 0.17) in the presence (absence) of an electric field.