Influence of growth direction and strain conditions on the band line-up at GaSb/InSb and InAs/InSb interfaces

TL;DR

This study uses first-principles calculations to analyze how growth direction and strain influence the band line-up at GaSb/InSb and InAs/InSb interfaces, revealing high tunability and agreement with experimental data.

Contribution

It provides detailed insights into the effects of epitaxial strain and growth direction on band offsets in III-V heterostructures using first-principles methods.

Findings

Valence band maximum is higher at InSb side except on InSb substrate.

Strain significantly affects the valence band offset, especially under pseudomorphic growth.

Calculated band line-up agrees with experimental results at InAs/GaSb interface.

Abstract

First-principles full potential linearized augmented plane wave (FLAPW) calculations have been performed for lattice-mismatched common-atom III-V interfaces. In particular, we have examined the effects of epitaxial strain and ordering direction on the valence band offset in [001] and [111] GaSb/InSb and InAs/InSb superlattices, and found that the valence band maximum is always higher at the InSb side of the heterojunction, except for the common-anion system grown on an InSb substrate. The comparison between equivalent structures having the same substrate lattice constant, but different growth axis, shows that for comparable strain conditions, the ordering direction slightly influences the band line-up, due to small differences of the charge readjustment at the [001] and [111] interfaces. On the other hand, strain is shown to strongly affect the VBO; in particular, as the pseudomorphic growth conditions are varied, the bulk contribution to the band line-up changes markedly, whereas the interface term is almost constant. On the whole, our calculations yield a band line-up that decreases linearly as the substrate lattice constant is increased, showing its high tunability as a function of different pseudomorphic growth conditions. Finally, the band line-up at the lattice matched InAs/GaSb interface determined using the transitivity rule gave perfect agreement between predicted and experimental results.