Strong interlayer interaction in two-dimensional layered PtTe2

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

“…The small interlayer spacing between MoS 2 and bilayer PtTe 2 leads to covalent-like ultrastrong forces benefiting from the strong thickness-dependent nature of PtTe 2 . 36,40,47 It is reported that PtTe 2 layers would evolve from semiconductive to metallic as the thickness increases owing to strong interlayer interactions, which provides complementary proof to our claim. 36 The differential charge density for the MoS 2 /PtTe 2 heterostructure (see Figure 4c) displays obvious charge redistribution at the interfacial layer, further indicating strong interlayer coupling between MoS 2 and PtTe 2 .…”

“…The PtTe 2 single crystal has a CdI 2 -type crystal structure (see Figure a), in which one Pt atom is surrounded by six Te atoms in a hexagonal repeating unit structure. , The interlayer spacing of 5.2 Å is very small in the family of 2D materials (e.g., 6.5 Å for MoS 2 ), which makes P z valence bands more dispersive and ultrastrong covalent-like interactions. The schematic linear and titled Dirac cones in Figure b represent type-I (e.g., graphene) and type-II (e.g., PtTe 2 ) semimetals, respectively. , To investigate the potential for the electrodes of 2D FETs, we first synthesized PtTe 2 nanoflakes through a two-step eutectic route, as shown in Figure c …”

“…36,40,47 It is reported that PtTe 2 layers would evolve from semiconductive to metallic as the thickness increases owing to strong interlayer interactions, which provides complementary proof to our claim. 36 The differential charge density for the MoS 2 /PtTe 2 heterostructure (see Figure 4c) displays obvious charge redistribution at the interfacial layer, further indicating strong interlayer coupling between MoS 2 and PtTe 2 . The binding energies of MoS 2 /PtTe 2 and MoS 2 /graphene are calculated to be 12.6 meV/Å 2 and 0.7 meV/Å 2 eV, respectively, further demonstrating that the MoS 2 /PtTe 2 heterostructure has a more stable structure and stronger interlayer coupling.…”

“…Besides the type-I Dirac semimetal represented by graphene, the layered PtTe 2 as a type-II Dirac semimetal is an emerging semimetallic material and has wide-ranging potential applications in mid-infrared and even terahertz photodetection. , It has been experimentally verified that PtTe 2 as electrodes can reduce contact resistance through an edge-to-edge connection between PtTe 2 and 2D semiconductors. , Those edge contacts based on a lateral heterostructure synthesized by the CVD route are incompatible with current semiconductor manufacturing processes . More importantly, PtTe 2 possesses an ultrastrong vdW force between interlayers, suggesting that the vertical contact between 2D semiconductors and PtTe 2 is expected to be more efficient . Li et al demonstrates that a well-defined OFF state can be achieved in MoS 2 -based devices, ascribed to the vdW interface between MoS 2 and PtTe 2 .…”

“…35 More importantly, PtTe 2 possesses an ultrastrong vdW force between interlayers, suggesting that the vertical contact between 2D semiconductors and PtTe 2 is expected to be more efficient. 36 Li et al demonstrates that a well-defined OFF state can be achieved in MoS 2 -based devices, ascribed to the vdW interface between MoS 2 and PtTe 2 . 37 Besides, the interlayer coupling through vdW interaction can also significantly affect the physical properties of vdW heterostructures, providing an essential degree of freedom for 2D materials.…”