Tunable Electronic Properties of Lateral Monolayer Transition Metal Dichalcogenide Superlattice Nanoribbons

The structural stability and structural and electronic properties of lateral monolayer transition metal chalcogenide superlattice zigzag and armchair nanoribbons have been studied by employing a first-principles method based on the density functional theory. The main focus is to study the effects of varying the width and periodicity of nanoribbon, varying cationic and anionic elements of superlattice parent compounds, biaxial strain, and nanoribbon edge passivation with different elements. The band gap opens up when the (MoS2)(3)/(WS2)(3) and (MoS2)(3)/(MoTe2)(3) armchair nanoribbons are passivated by H, S and O atoms. The H and O co-passivated (MoS2)(3)/(WS2)(3) armchair nanoribbon exhibits higher energy band gap. The band gap with the edge S vacancy connecting to the W atom is much smaller than the S vacancy connecting to the Mo atom. Small band gaps are obtained for both edge and inside Mo vacancies. There is a clear difference in the band gap states between inside and edge Mo vacancies for symmetric nanoribbon structure, while there is only a slight difference for asymmetric structure. The electronic orbitals of atoms around Mo vacancy play an important role in determining the valence band maximum, conduction band minimum, and impurity level in the band gap.

Automated summary

The study examined the structural stability and electronic properties of lateral monolayer transition metal chalcogenide superlattice nanoribbons, focusing on the effects of varying width, periodicity, cationic and anionic elements, biaxial strain, and edge passivation on the band gap. Various combinations of elements for passivation were found to affect the energy band gap, with differences in band gap states observed between edge and inside vacancies. The electronic orbitals around Mo vacancies were found to play a crucial role in determining band gap properties.