Improving Contacts and Electrical Performances of Nanofilms of MoS₂ Transistors through Ultrastrong vdW Integration with Dirac Semimetal PtTe₂

Semiconductor–metal contacts as one major challenge have severely hindered the further progress of two-dimensional (2D) electronics. Here, we present a simple and effective strategy to improve the contacts and electrical performances by fabricating van der Waals (vdW) heterostructures with 2D semiconductor MoS 2 and type-II Dirac semimetal PtTe 2 . The semiconductor MoS 2 and Dirac semimetal PtTe 2 nanoflakes are synthesized through CVD routes separately, followed by systematic material characterizations to confirm their structures. Furthermore, we constructed MoS 2 /PtTe 2 vdW heterostructures via a transfer technology with as-grown MoS 2 and PtTe 2 nanoflakes. The field-effect transistor based on MoS 2 /PtTe 2 heterostructures shows ohmic contact and improved electrical performances, such as two-terminal carrier mobility (∼38.2 cm 2 ·V –1 ·s –1 ) and ON/OFF ratio (∼10 4 ). We ascribe the improvement of contact and electrical performances to the utilization of ultrahigh-conductive layered PtTe 2 as an interlayer. The theoretical calculations demonstrate that the vdW contact can eliminate the Fermi level pinning effect; meanwhile, the ultrastrong covalent-like interlayer coupling guarantees the high-efficiency carrier injection across PtTe 2 and MoS 2 . The concept that synergizes 2D semiconductors as the channel and Dirac semimetal PtTe 2 as an interlayer will offer a promising approach toward the design of high-performance 2D electronics.