Engineering the electronic properties of MoTe via defect control.

The remarkable electronic properties of monolayer MoTe make it a very adaptable material for use in optoelectronic and nano-electronic applications. MoTe 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 MoTe 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 MoTe. 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 MoTe 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 MoTe, suggesting its potential as a new platform for electronic applications. Hence, our analysis offers significant theoretical backing for defect engineering in MoTe monolayers and other 2D materials, a critical aspect in the advancement of nanoscale devices with the desired functionality.