Structural properties and stability of defected ZnSe/GaAs(001) interfaces

TL;DR

This study uses ab-initio density functional theory calculations to analyze the structural properties and stability of defected ZnSe/GaAs(001) interfaces, revealing conditions favoring vacancy-containing structures.

Contribution

It provides new insights into the microscopic mechanisms and thermodynamic conditions that stabilize defected interfaces in ZnSe/GaAs heterostructures.

Findings

Vacancies can stabilize interfaces under specific conditions.

Certain defected configurations are energetically favored.

Results align with experimental evidence of vacancies at interfaces.

Abstract

Accurate ab-initio pseudopotential calculations within density functional theory in the LDA approximation have been performed for structural properties and stability of ZnSe/GaAs(001) defected heterostructures. There is a strong experimental evidence that ZnSe/GaAs heterostructures with minimum stacking fault density are related to the presence of a substantial concentration of Ga vacancies at interface. In order to gain insights into the still unknown microscopic maechanism governing their formation and stability, we compared the relative stability of some simple selected interface configurations, chosen taking into account charge neutrality prescription and allowing the presence of Ga vacancy next to the interface. Remarkably, our results show that, under particular thermodynamic conditions, some interfaces with vacancies are favoured over undefected ones.