Formation of In-Plane Semiconductor–Metal Contacts in 2D Platinum Telluride by Converting PtTe₂ to Pt₂Te₂

Abstract

Monolayer PtTe2 is a narrow gap semiconductor while Pt2Te2 is a metal. Here we show that the former can be transformed into the latter by reaction with vapor-deposited Pt atoms. The transformation occurs by nucleating the Pt2Te2 phase within PtTe2 islands, so that a metal–semiconductor junction is formed. A flat band structure is found with the Fermi level of the metal aligning with that of the intrinsically p-doped PtTe2. This is achieved by an interface dipole that accommodates the ∼0.2 eV shift in the work functions of the two materials. First-principles calculations indicate that the origin of the interface dipole is the atomic scale charge redistributions at the heterojunction. The demonstrated compositional phase transformation of a 2D semiconductor into a 2D metal is a promising approach for making in-plane metal contacts that are required for efficient charge injection and is of particular interest for semiconductors with large spin–orbit coupling, like PtTe2.

PtTe2/Sb2S3 Nanoscale Heterostructures for the Photocatalytic Direct Z-Scheme with High Solar-to-Hydrogen Efficiency: A Theoretical Investigation

“…52 This direction of the E built-in and the band alignments of the two configurations support them to work as a Z-scheme rather than type-II photocatalytic performance. Additionally, the present band alignments and direction of the built-in electric field are similar to those of the p−n heterojunctions containing PtTe 2 or Sb 2 S 3 , 20,24,53 implying that a weak p−n heterojunction may also occur in the present heterostructure. As shown in Figure 3, the E built-in accelerates the recombination of the photogenerated hole at the VBM of the PtTe 2 monolayer and the electron at the CBM of the Sb 2 S 3 monolayer.…”

“…The nanoscale vdW heterostructures with different 2D ultrathin functional nanosheets can often achieve satisfactory photocatalytic performance with a direct Z-scheme if a suitable band alignment is constructed. , Here, we demonstrate that the PtTe 2 /Sb 2 S 3 nanoscale heterostructure can also achieve high η STH ′ with the direct Z-scheme. The PtTe 2 monolayer as a member of the TMD family has been prepared in the experiment and is similar to the synthesized PtTe 2 /Pt 2 Te 2 nanoscale heterostructures . Recently, the potential use of the PtTe 2 monolayer in a variety of different applications, such as electrocatalysis, ultrafast photonics, and terahertz photodetection, has been reported.…”

“…The PtTe 2 monolayer as a member of the TMD family has been prepared in the experiment 19 and is similar to the synthesized PtTe 2 /Pt 2 Te 2 nanoscale heterostructures. 20 Recently, the potential use of the PtTe 2 monolayer in a variety of different applications, such as electrocatalysis, 21 ultrafast photonics, 22 and terahertz photodetection, 23 has been reported. Sb 2 S 3 as a member of the antimony chalcogenide compounds and an n-type semiconductor has been widely applied in the fields of the photovoltaic device in view of its excellent stability, earth abundance, good light harvesting, and easy to prepare.…”

A van der Waals Heterostructure with an Electronically Textured Moiré Pattern: PtSe2/PtTe2

“…PtTe 2 and PtSe 2 are grown in dedicated tellurium and selenium growth chambers by co-deposition of Pt and chalcogens. First a PtTe 2 multilayer film is grown at 300 °C substrate temperature on a freshly cleaved and vacuum-annealed HOPG substrate. , Subsequently, a monolayer of PtSe 2 is grown on top of the PtTe 2 at a growth temperature of 300 °C. For both compounds, Pt was evaporated in an e-beam evaporator from a 2 mm solid Pt rod.…”

Electric Field Induced Schottky to Ohmic Contact Transition in Fe3GeTe2/TMDs Contacts

“…Two-dimensional (2D) transition metal dichalcogenides (TMDs) semiconductors have presented great potential as the channel materials for field effect transistors (FETs) due to their high carrier mobility and large on/off ratio. − TMDs-based FETs have been widely investigated and have demonstrated that they are advantageous over the other nanomaterial-based FETs, which are attributed to the dangling-bond-free surface and the moderate band gaps of TMDs. − However, the contact between metal electrodes and TMDs is inevitable. The Schottky barrier is commonly formed at the contact interface, which will impede the charge injection efficiency. − Thus, reducing the Schottky barrier height (SBH) is desirable for designing the high-performance electrical devices.…”