Thermodynamic stability of defects in hybrid MoS2/InAs heterostructures

Abstract

Vertical van der Waals heterostructures created from two chemically different two-dimensional (2D) materials have made significant headway in the current electronic manufacturing landscape since they demonstrate enhanced attributes. Recently, among the wide variety of possible van der Waals heterostructures, a 2D molybdenum disulfide (MoS2) thin film deposited on a 3D indium arsenide (InAs) semiconductor substrate has demonstrated promising properties. To realize the true potential of these hybrid heterostructures, it is imperative to understand their structural stability, as well as the thermodynamic stabilities of various defects at the heterointerface. We report first principles-based electronic structure calculations to study MoS2(100)/InAs(111) heterostructures with two different terminations of the substrate. We present relative stabilities of arsenic-terminated and indium-terminated heterostructures, and shed light on the thermodynamic stabilities of arsenic, indium, and sulfur vacancy defects at the heterointerface. Atomic-scale structure and electronic structure of defects is detailed along with changes in band gaps due to inclusion of vacancy defects. In general, defects are found to be energetically favorable to occur at the interface as compared to the bulk. We offer new insights into the fundamental role of interfaces in hybrid van der Waals heterostructures and their influence on defects, with potential implications for future design of next-generation semiconductors.