Interface quality in GaSb/AlSb short period superlattices

TL;DR

This study investigates methods to improve interface sharpness in AlSb/GaSb short-period superlattices, revealing a wide growth window for achieving high-quality interfaces using various interventions.

Contribution

It systematically tests interventions like substrate temperature, flux ratio, and surfactants to enhance interface quality in AlSb/GaSb superlattices.

Findings

Wide growth window for sharp interfaces in AlSb/GaSb superlattices

Interventions can effectively improve interface sharpness

High-resolution characterization confirms interface quality

Abstract

Heterostructures including the members of the 6.1{\AA} semiconductor family (AlSb, GaSb, and InAs) are used in infrared optoelectronic devices as well as a variety of other applications. Short-period superlattices of these materials are also of interest for creating composite materials with designer infrared dielectric functions. The conditions needed to create sharp InAs/GaSb and InAs/AlSb interfaces are well known, but the AlSb/GaSb interface is much less well-understood. In this article, we test a variety of interventions designed to improve interface sharpness in AlSb/GaSb short-period superlattices. These interventions include substrate temperature, III:Sb flux ratio, and the use of a bismuth surfactant. Superlattices are characterized by high-resolution x-ray diffraction and infrared spectroscopy. We find that AlSb/GaSb short-period superlattices have a wide growth window over which sharp interfaces can be obtained.