Stability of defects at MoS₂/InAs hybrid heterostructures

Vertical van der Waals heterostructures created from two chemically different two-dimensional (2D) materials have made significant headway in the current electronic manufacturing landscape. They demonstrate enhanced electronic properties and have the potential to be used in high performance electronic devices. Among the various van der Waals heterostructures, molybdenum disulfide (MoS₂) thin film on an indium arsenide (InAs) substrate has shown promising opto-electronic properties. This hybrid heterostructure gives stronger optical absorption properties than a 2D layer of graphene on InAs due to smaller equilibrium spacing. To realize the true potential of these heterostructures, it is imperative to understand not only their stability, but also the thermodynamic stability of various defects at the heterointerface. We have performed first principles density functional theory calculations to study MoS₂(100)/InAs(111) heterostructures with two different terminations of the substrate. We will discuss the thermodynamic stabilities of In-terminated and As-terminated heterostructures and shed light on the stabilities of S, In, and As vacancy defects at the heterointerface. Overall, our results offer insights into the fundamental role of defects in van der Waals heterostructures.