Nanohole etching in AlGaSb with Ga droplets

TL;DR

This paper explores nanohole formation in AlGaSb using Ga droplet etching across a broad temperature range, providing insights into the physics of adatom diffusion and control over nanostructure fabrication.

Contribution

It introduces a geometric diffusion-based model linking temperature and Sb flux to nanohole formation, advancing understanding of droplet-mediated semiconductor nanostructure synthesis.

Findings

Controlled nanohole density over a wide temperature range

Determined critical Sb monolayer coverage for etching completion

Revealed physics of adatom diffusion in droplet etching processes

Abstract

We demonstrate nanohole formation in AlGaSb by Ga droplet etching within a temperature range from 270{\deg}C to 500{\deg}C, allowing a wide range of tunability of the nanohole density. By leveraging the low vapor pressure of Sb, we can obtain high degree of control over droplet formation and nanohole etching steps and reveal the physics of adatom diffusion in these processes. Furthermore, by combining the experimental results and a geometric diffusion-based model, we can determine the temperature and Sb-flux-dependencies of the critical monolayer coverage of Sb atoms required for driving the droplet etching process to completion. These findings provide new insight into the droplet formation and etching process present in the droplet-mediated synthesis of semiconductor nanostructures and represent a significant step towards development of telecom-emitting quantum dots in the GaSb system.