10.1021/acsami.7b02739.s001
Pantelis Bampoulis
Pantelis
Bampoulis
Rik van Bremen
Rik
van Bremen
Qirong Yao
Qirong
Yao
Bene Poelsema
Bene
Poelsema
Harold J. W. Zandvliet
Harold
J. W. Zandvliet
Kai Sotthewes
Kai
Sotthewes
Defect
Dominated Charge Transport and Fermi Level Pinning in MoS<sub>2</sub>/Metal Contacts
American Chemical Society
2017
future MoS 2
Natural MoS 2
Schottky barrier height
Fermi Level Pinning
high-spatial-resolution surface characterization techniques
MoS 2
device junction contact area decreases
low-resistance conduction paths
outermost S atom
metal-like defects
2017-05-16 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Defect_Dominated_Charge_Transport_and_Fermi_Level_Pinning_in_MoS_sub_2_sub_Metal_Contacts/5038742
Understanding the
electronic contact between molybdenum disulfide (MoS<sub>2</sub>)
and metal electrodes is vital for the realization of future MoS<sub>2</sub>-based electronic devices. Natural MoS<sub>2</sub> has the
drawback of a high density of both metal and sulfur defects and impurities.
We present evidence that subsurface metal-like defects with a density
of ∼10<sup>11</sup> cm<sup>–2</sup> induce negative
ionization of the outermost S atom complex. We investigate with high-spatial-resolution
surface characterization techniques the effect of these defects on
the local conductance of MoS<sub>2</sub>. Using metal nanocontacts
(contact area < 6 nm<sup>2</sup>), we find that subsurface metal-like
defects (and not S-vacancies) drastically decrease the metal/MoS<sub>2</sub> Schottky barrier height as compared to that in the pristine
regions. The magnitude of this decrease depends on the contact metal.
The decrease of the Schottky barrier height is attributed to strong
Fermi level pinning at the defects. Indeed, this is demonstrated in
the measured pinning factor, which is equal to ∼0.1 at defect
locations and ∼0.3 at pristine regions. Our findings are in
good agreement with the theoretically predicted values. These defects
provide low-resistance conduction paths in MoS<sub>2</sub>-based nanodevices
and will play a prominent role as the device junction contact area
decreases in size.