# Interplay between Quantum Well Width and Interface Roughness for Electron Transport Mobility in GaAs Quantum Wells

## TL;DR

This study investigates how quantum well width and interface roughness affect electron mobility in GaAs quantum wells, revealing the interplay between physical structure and electron transport efficiency.

## Contribution

It provides experimental data showing the effects of interface roughness and wave function penetration on mobility in different GaAs quantum well structures.

## Key findings

- Mobility in narrow QWs without cladding aligns with theoretical models.
- AlAs-clad wells exhibit mobility limitations due to interface roughness.
- A comprehensive mobility map across various structures and conditions.

## Abstract

We report transport mobility measurements for clean, two-dimensional (2D) electron systems confined to GaAs quantum wells (QWs), grown via molecular beam epitaxy, in two families of structures, a standard, symmetrically-doped GaAs set of QWs with Al$_{0.32}$Ga$_{0.68}$As barriers, and one with additional AlAs cladding surrounding the QWs. Our results indicate that the mobility in narrow QWs with no cladding is consistent with existing theoretical calculations where interface roughness effects are softened by the penetration of the electron wave function into the adjacent low barriers. In contrast, data from AlAs-clad wells show a number of samples where the 2D electron mobility is severely limited by interface roughness. These measurements across three orders of magnitude in mobility provide a road map of reachable mobilities in the growth of GaAs structures of different electron densities, well widths, and barrier heights.