Diverse Responses in Lattice Thermal Conductivity of $n$-type/$p$-type Semiconductors Driven by Asymmetric Electron-Phonon Interactions

TL;DR

This study uses first-principles calculations to reveal how asymmetric electron-phonon interactions differently affect the lattice thermal conductivity in n-type and p-type semiconductors, depending on doping type and bandgap nature.

Contribution

It provides a detailed first-principles analysis of the asymmetric effects of electron-phonon interactions on thermal conductivity in semiconductors, highlighting the role of electronic structure.

Findings

EPI impacts p-type doping more than n-type at high carrier concentrations.

Stronger EPI in p-type doping is due to higher electron density of states from p-orbitals.

EPI influences indirect bandgap semiconductors more than direct ones in n-type doping.

Abstract

Accurately assessing the impact of electron-phonon interaction (EPI) on the lattice thermal conductivity of semiconductors is crucial for the thermal management of electronic devices and a unified physical understanding of this issue is highly desired. In this work, we predict the lattice thermal conductivities of typical direct and indirect bandgap semiconductors accounting for EPI based on mode-level first-principles calculations. It is found that EPI has a larger effect on the lattice thermal conductivity of $p$-type doping compared to $n$-type doping in the same semiconductor at high charge carrier concentrations. The stronger EPI in $p$-type doping is attributed to the relatively higher electron density of states caused by the relatively larger $p$-orbital component. Furthermore, EPI has a stronger influence on the lattice thermal conductivity of $n$-type indirect bandgap semiconductors than $n$-type direct bandgap semiconductors. This is attributed to the relatively lower electron density of states in direct bandgap semiconductors stemming from the $s$-orbital component. This work reveals that there exist diverse responses in lattice thermal conductivity of $n$-type/$p$-type semiconductors, which can be attributed to asymmetric EPIs.