Size and pressure dependence lattice thermal conductivity of Wurtzite GaN nanowires

Abstract

The size and pressure effect on lattice thermal conductivity (LTC) of Wurtzite GaN NWs with diameters of 97, 100, 126, and 160 nm in the temperature range (2–350) K fitted to those reported experimental data. The investigations were based on the Debye-Callaway model along with the Clapeyron and Murnaghan equations, for both longitudinal and transverse modes of phonons. by considering in the calculations, the nanosized dependence of melting temperature, lattice volume, Debye temperature, and group velocity. Nanosized melting temperature is used to calculate its related parameters of melting enthalpy, melting entropy, and surface energy. In this work, the nanosized dependence relation for the Gruneisen parameter gives values of 0.14475 for 160 nm and increases to 0.14535 for 97 nm. While its modification due to the applied pressure reduces its value. The relations are obtained for the nanosized dependence of surface roughness, Casimir length, dislocation concentration and lattice scattering factor, enabling this model to obtain LTC free from fitting parameters. The model was then applied successfully on 50 and 30 nm NWs diameter for this binary semiconductor.