Simultaneous study of acoustic and optic phonon scattering of electrons and holes in undoped $\mathrm{GaAs}$/$\mathrm{Al_{x} Ga_{1-x} As}$ heterostructures

TL;DR

This paper investigates phonon scattering of electrons and holes in undoped GaAs/AlGaAs heterostructures across a wide temperature range, providing insights into electron-phonon interactions without doping-related complications.

Contribution

It introduces a method to study phonon coupling in undoped heterostructures over a broad temperature range, avoiding issues from dopant effects and enabling direct measurement of phonon interactions.

Findings

Measured phonon coupling constants for electrons and holes.

Determined LO phonon activation energy.

Validated results with alternative approaches.

Abstract

The study of phonon coupling in doped semiconductors via electrical transport measurements is challenging due to unwanted temperature-induced effects such as dopant ionisation and parallel conduction. Here, we study phonon scattering in 2D electrons and holes in the $1.6-92.5$K range without the use of extrinsic doping, where both acoustic and longitudinal optic (LO) phonons come into effect. We use undoped GaAs/$\mathrm{Al_{x} Ga_{1-x} As}$ heterostructures and examine the temperature dependence of the sample resistivity, extracting phonon coupling constants and the LO activation energy. Our results are consistent with results obtained through approaches other than transport measurements, and highlight the benefit of this approach for studying electron-phonon and hole-phonon coupling.