Electron Heat Source Driven Heat Transport in GaN at Nanoscale: Electron–Phonon Monte Carlo Simulations and a Two Temperature Model

Abstract

The thermal energy transport in semiconductors is mostly determined by phonon transport. However in polar semiconductors like GaN electronic contribution to the thermal transport is non-negligible. In this paper, we use an electron–phonon Monte Carlo (MC) method to study temperature distribution and thermal properties in a two-dimensional GaN computational domain with a localized, steady and continuous electron heat source at one end. Overall, the domain mimics the two-dimensional electron gas (2DEG) channel of a typical GaN high electron mobility transistor (HEMT). High energy electrons entering the domain from the source interact with the phonons, and drift under the influence of an external electric field. Cases of the electric field being uniform and non-uniform are investigated separately. A two step/temperature analytical model is proposed to describe the electron as well as phonon temperature profiles and solved using the finite difference method (FDM). The FDM results are compared with the MC results and found to be in good agreement.

Nonequilibrium electron–phonon coupling across the interfaces between Al nanofilm and GaN

“…Ultrafast diffuse-scattering experiments and first-principles calculations confirmed local thermal nonequilibrium of phonons, 26,27 indicating significant deviations from Bose-Einstein statistics in e-ph coupling and phonon population. Cao et al 28 investigated electron-phonon interactions in a two-dimensional GaN computational domain with a localized, stabilized, and continuous electron heat source at one end by means of an electron-phonon Monte Carlo method, and it was found that high-energy electrons interacting with the phonons drifted under the influence of an external electric field. Li et al 29 introduced a novel model that comprises two distinct coupling mechanisms to elucidate the cross-interface electron-phonon heat transfer process.…”

Phonon Transport Characteristics of Nano-Silicon Thin Films Irradiated by Ultrafast Laser under Dispersion Relation

“…In recent years, the LBM has been widely used in simulating the transport processes of electrons and phonons [22][23][24]. Compared to the classical Fourier's law and molecular dynamics methods [25,26], the LBM has advantages in terms of high computational efficiency and convenient handling of boundary conditions [27].…”

A problem with periodic boundary conditions for the non-Fourier heat equation

“…[34,16], can give rise to non-Fourier phenomena. These include size-dependent thermal behavior, variations in conductivity, and abrupt changes in boundary temperatures [10].…”

“…Nonlocal spatial influences [37] have been extensively examined in various domains. These include the realm of thermal conductivity within nanoscale systems [34,10,23], as well as in metals exposed to ultra-brief laser irradiation, spanning picoseconds and femtoseconds [39,38,31,27,45]. Furthermore, nonlocal spatial effects have garnered attention in contexts such as biological systems, cf.…”