Defect dependent electronic properties of WTe2: a first-principles study

Abstract

Tungsten ditelluride (WTe2) possesses fascinating electronic structures and exceptional properties that make it highly suitable for use in cutting-edge devices. Defects in WTe2 can have a significant influence on its properties, both in advantageous and disadvantageous ways. Thus, a precise classification is crucial to fully comprehend the potential impacts. Here we report a thorough investigation of the electronic characteristics of intrinsic defects, including point defects, in monolayer WTe2 using first-principles calculations based on density functional theory. Our research suggests that the presence of point defects can cause a notable shift in electronic properties, resulting in a metallic behaviour. This is due to the interesting phenomenon of Fermi-level changing near the band edges. Our research findings indicate that the energy required to form a vacancy in a Te atom is lower compared to that of a vacancy in a W atom. Based on the findings, it appears that Te atom vacancies are more likely to be generated during the synthesis process. Defects like the Te vacancy and Mo substitution in the pristine monolayer of WTe2 result in a subtle reduction in the band gap, while still maintaining its characteristics as a direct band gap semiconductor. Our study reveals that the electronic properties of monolayer WTe2 can be significantly altered by the presence of vacancy defects. This discovery highlights the exciting potential of WTe2 as a promising platform for various electronic applications. Our research is anticipated to have a beneficial impact on the comprehension and control of the characteristics of WTe2, thus expediting the development of nanomaterials in various fields.