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Structural and electronic properties of defective 2D transition metal dichalcogenide heterostructures
Author(s) -
Pecoraro Adriana,
Schiavo Eduardo,
Maddalena Pasqualino,
MuñozGarcía Ana B.,
Pavone Michele
Publication year - 2020
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.26364
Subject(s) - heterojunction , density functional theory , electronic structure , maxima and minima , hybrid functional , band gap , monolayer , materials science , chemical physics , vacancy defect , electronic band structure , water splitting , molecular physics , chemistry , condensed matter physics , optoelectronics , computational chemistry , nanotechnology , photocatalysis , crystallography , physics , catalysis , mathematical analysis , biochemistry , mathematics
We present a first‐principles study on the structure‐property relationships in MoS 2 and WS 2 monolayers and their vertically stacked hetero‐bilayer, with and without Sulfur vacancies, in order to dissect the electronic features behind their photocatalytic water splitting capabilities. We also benchmark the accuracy of three different exchange‐correlation density functionals for both minimum‐energy geometries and electronic structure. The best compromise between computational cost and qualitative accuracy is achieved with the HSE06 density functional on top of Perdew–Burke–Ernzerhof minima, including dispersion with Grimme's D3 scheme. This computational approach predicts the presence of mid‐gap states for defective monolayers, in accordance with the present literature. For the heterojunction, we find unexpected vacancy‐position dependent electronic features: the location of the defects leads either to mid‐gap trap states, detrimental for photocatalyst or to a modification of characteristic type II band alignment behavior, responsible for interlayer charge separation and low recombination rates.