Electronic properties of MoS2/MoOxinterfaces: Implications in Tunnel Field Effect Transistors and Hole Contacts.
In an electronic device based on two dimensional (2D) transitional metal dichalcogenides (TMDs), finding a low resistance metal contact is critical in order to achieve the desired performance. However, due to the unusual Fermi level pinning in metal/2D TMD interface, the performance is limited. Here, we investigate the electronic properties of TMDs and transition metal oxide (TMO) interfaces (MoS2/MoO3) using density functional theory (DFT). Our results demonstrate that, due to the large work function of MoO3and the relative band alignment with MoS2, together with small energy gap, the MoS2/MoO3interface is a good candidate for a tunnel field effect (TFET)-type device. Moreover, if the interface is not stoichiometric because of the presence of oxygen vacancies in MoO3, the heterostructure is more suitable for p-type (hole) contacts, exhibiting an Ohmic electrical behavior as experimentally demonstrated for different TMO/TMD interfaces. Our results reveal that the defect state induced by an oxygen vacancy in the MoO3aligns with the valance band of MoS2, showing an insignificant impact on the band gap of the TMD. This result highlights the role of oxygen vacancies in oxides on facilitating appropriate contacts at the MoS2and MoOx(x < 3) interface, which consistently explains the available experimental observations.
Department of Materials Science &Engineering, The University of Texas at Dallas, Richardson, TX 75080 USA.|Materials Science and Technology Division, Oak Ridge National Laboratory, Bethel Valley Road, Oak Ridge, Tennessee 37831, USA.
Santosh
S
K C
Department of Materials Science &Engineering, The University of Texas at Dallas, Richardson, TX 75080 USA.
Roberto C
RC
Longo
Department of Materials Science &Engineering, The University of Texas at Dallas, Richardson, TX 75080 USA.
Rafik
R
Addou
Department of Materials Science &Engineering, The University of Texas at Dallas, Richardson, TX 75080 USA.|Department of Physics, The University of Texas at Dallas, Richardson, TX 75080 USA.
Robert M
RM
Wallace
Department of Materials Science &Engineering, The University of Texas at Dallas, Richardson, TX 75080 USA.|Department of Physics, The University of Texas at Dallas, Richardson, TX 75080 USA.
Kyeongjae
K
Cho
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