Atomic Structure of Intrinsic and Electron-Irradiation-Induced
Defects in MoTe<sub>2</sub>
Kenan Elibol
Toma Susi
Giacomo Argentero
Mohammad Reza Ahmadpour Monazam
Timothy J. Pennycook
Jannik C. Meyer
Jani Kotakoski
10.1021/acs.chemmater.7b03760.s002
https://acs.figshare.com/articles/dataset/Atomic_Structure_of_Intrinsic_and_Electron-Irradiation-Induced_Defects_in_MoTe_sub_2_sub_/5887078
Studying
the atomic structure of intrinsic defects in two-dimensional
transition-metal dichalcogenides is difficult since they damage quickly
under the intense electron irradiation in transmission electron microscopy
(TEM). However, this can also lead to insights into the creation of
defects and their atom-scale dynamics. We first show that MoTe<sub>2</sub> monolayers without protection indeed quickly degrade during
scanning TEM (STEM) imaging, and discuss the observed atomic-level
dynamics, including a transformation from the 1H phase into 1T′,
3-fold rotationally symmetric defects, and the migration of line defects
between two 1H grains with a 60° misorientation. We then analyze
the atomic structure of MoTe<sub>2</sub> encapsulated between two
graphene sheets to mitigate damage, finding the as-prepared material
to contain an unexpectedly large concentration of defects. These include
similar point defects (or quantum dots, QDs) as those created in the
nonencapsulated material and two different types of line defects (or
quantum wires, QWs) that can be transformed from one to the other
under electron irradiation. Our density functional theory simulations
indicate that the QDs and QWs embedded in MoTe<sub>2</sub> introduce
new midgap states into the semiconducting material and may thus be
used to control its electronic and optical properties. Finally, the
edge of the encapsulated material appears amorphous, possibly due
to the pressure caused by the encapsulation.
2018-02-05 00:00:00
material
MoTe 2 monolayers
1 H grains
1 H phase
MoTe 2 encapsulated
MoTe 2
TEM
transmission electron microscopy
electron irradiation
line defects
QW
QD