The band alignments modulation of g–MoTe2/WTe2 van der Waals heterostructures
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Searching for novel two-dimensional (2D) materials based nanoscale electronic devices is a hot topic in the current research. A modulation of materials’ specific physical properties by altering external conditions has long been used. There are a variety of routes to improve the specific behavior of materials. In this paper, the structural, electronic, and the corresponding variational characteristics of the graphene(g)-MoTe2/WTe2 heterointerfaces are studied in detail based on ab initio calculations with nonlocal van der Waals (vdW) corrections. We performed research on the band alignments of g–MoTe2/WTe2 contacts and a concise routine to reduce the Schottky barrier and obtain Ohmic contact. The results predict a barrier height of 62 meV and 280 meV for g–MoTe2/WTe2, respectively, in a neutral state. In the applied electric field, the corresponding Schottky barriers can be effectively tuned by various electric fields. The height of the barrier further decreases to 0 under − 0.02/0.16 V/Å and − 0.06/0.08 V/Å for g–MoTe2/WTe2, respectively, and the numerical value of the barrier and the corresponding Schottky type can be regulated in a flexible way. Additionally, theoretical calculation results also demonstrate that g–MoTe2 has a smaller Fermi level pinning effect than g–WTe2, which plays a significant role in the fabrication of novel transistors based 2D materials and it should be a better choice for FETs application.
The authors acknowledge financial support by the Science and Technology Research Program of Chongqing Municipal Education Commission (Grant No. KJQN201800501, KJQN201800528), the Program for Leading Talents in Science and Technology Innovation of Chongqing City (No. cstc2014kjcxljrc0023) and Chongqing Normal University Fund Project (Grant No. 17XLB012).
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Conflict of interest
The authors declare no competing financial interest.
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