Engineering the electronic properties of MoTe₂ via defect control

The remarkable electronic properties of monolayer MoTe₂ make it a very adaptable material for use in optoelectronic and nano-electronic applications. MoTe₂ growth often exhibits intrinsic defects, which significantly influence the material's characteristics. In this work, we conducted a thorough investigation of the electronic characteristics of intrinsic defects, including point defects, in monolayer MoTe₂ using first-principles calculations based on density functional theory (DFT). Our findings indicate that the presence of point defects leads to the formation of n-type properties as the Fermi level situates above the conduction band. Our first-principles density functional theory calculation revealed an appearance of donor level in the band gap close to the conduction band in MoTe₂. Our study signifies that the formation energy of a vacancy in a Te atom is lower than that of both a vacancy in a Mo atom and two vacancies in Te atom. This suggests that during the synthesis process, it is more probable for Te atom vacancies to be created. A defect in the pristine monolayer of MoTe₂ leads to a slight decrease in the band gap, causing a transition from a direct band gap semiconductor to an indirect band gap semiconductor. The results of our study indicate that the presence of vacancy defects may modify the electronic properties of monolayer MoTe₂, suggesting its potential as a new platform for electronic applications. Hence, our analysis offers significant theoretical backing for defect engineering in MoTe₂ monolayers and other 2D materials, a critical aspect in the advancement of nanoscale devices with the desired functionality.