Electronic Properties and Scanning Tunneling Microscopy Simulation of MoS2 Nanosheets by Using Density Functional Theory

Abstract

The ab-initio Density Functional Theory (DFT) approach is used to study the electronic properties of bulk and layered MoS₂ nanosheets. For the layered structures mono, bi, tri, tetra and penta layered structure is used. The direct to indirect transition of bandgap is observed as the number of layers is increasing. This transition of bandgap is attributed to the van der Waals interlayer interaction between two layers of MoS₂ nanosheets. The indirect bandgap in the bulk MoS₂ is found to be 0.94 eV, whereas for a single layered nanosheet is found to be direct bandgap with the value of 1.83 eV. To confirm the surface termination and understand the surface morphology of MoS₂ the scanning tunneling microscopy (STM) simulation is performed in constant height mode. It is found that the detection of surface atoms via STM depends on the tip atom of the STM.

Dhaka Univ. J. Sci. 69(1): 53-57, 2021 (January)