Intriguing electronic properties of two-dimensional MoS₂/TM₂CO₂(TM = Ti, Zr, or Hf) hetero-bilayers: type-II semiconductors with tunable band gaps

Abstract

Two-dimensional (2D) transition metal compound (TMC) monolayers, as well as their van der Waals heterostructures with unique properties, are fundamentally and technologically intriguing. Here, heterostructures consisting of a MoS2 monolayer and TM2CO2 (TM = Ti, Zr or Hf) monolayers are systematically researched by means of the density functional theory (DFT). Different from semiconductor/metal contacts, MoS2 and TM2CO2 monolayers are all semiconductors with band gaps ranging from 0.25-1.67 eV. According to rigorous screening of stacking patterns, MoS2/Zr2CO2 is shown to be an indirect type-II semiconductor with the maximum valence and minimum conduction bands spatially separated on opposite monolayers. Simultaneously, the interface charges transfer from Zr2CO2 to MoS2 results in a built-in field that separates the electrons and holes efficiently. Also, the smaller effective masses of electrons and the holes of band edges indicate the higher carrier mobility. Moreover, strain regulation can make the hetero-bilayer's character a semiconductor-semimetal-metal transition. The physical insights pave the way for the good performance of MoS2/TM2CO2 in next-generation electronic devices and photocatalysts.

Recent advances in MXene: Preparation, properties, and applications

“…In fields other than electrochemistry, MXenes' unique structures and properties provide the material class with many other potential applications, including adsorbents [16,65], hydrogen storage media [66,67], catalyst supporters [21,68,69], additives [70,71], and many others [72][73][74][75]. However, many of these applications are still hypothetical or at the fundamental stage.…”

Growth of WS2 flakes on Ti3C2Tx Mxene Using Vapor Transportation Routine

“…A heterostructure composed by mxene and TMDs had been predicted to have tunable band structures [12,13]. Ma et al [13] predicted the band gap of Sc 2 CF 2 /TMDs can be largely tuned from 0.13 to 1.18 eV by using density function theory (DFT) calculations.…”

“…Ma et al [13] predicted the band gap of Sc 2 CF 2 /TMDs can be largely tuned from 0.13 to 1.18 eV by using density function theory (DFT) calculations. Li et al calculated the band structure of MoS 2 /M 2 CO 2 (M = Ti, Sc and Hf) and also found these heterostructures show a large tunable band gap as 0.25-1.67 eV [12]. Moreover, MoS 2 /Zr 2 CO 2 was predicted to exhibit an interesting type-II semiconductor feature with conduction and valance bands in different layers [12].…”

“…Li et al calculated the band structure of MoS 2 /M 2 CO 2 (M = Ti, Sc and Hf) and also found these heterostructures show a large tunable band gap as 0.25-1.67 eV [12]. Moreover, MoS 2 /Zr 2 CO 2 was predicted to exhibit an interesting type-II semiconductor feature with conduction and valance bands in different layers [12]. These distinct properties intrigued their applications in novel devices.…”

MXene‐Based Composites: Synthesis and Applications in Rechargeable Batteries and Supercapacitors

“…[48] M 3 X 2 T x ratios MXenes have revealed drawbacks such as restacking, easy oxidation, and low electrical conductivity, inhibiting the development of pure M 3 X 2 T x . So far, the MXene-based composites have been successfully synthesized with metals, [59][60][61][62] metal sulfides, [63] metal oxides, [60,64,65] mesoporous carbon, [66,67] graphene, [68] high-quality graphene, [69] carbon nanotubes, [70] carbon fibers, [71,72] polypyrrole, [73] etc., and its applications have been exploited in various fields, for instance, batteries, [74] supercapacitors (SCs), [75] electromagnetic wave absorption, [59,76] water purification, [77] etc. So far, the MXene-based composites have been successfully synthesized with metals, [59][60][61][62] metal sulfides, [63] metal oxides, [60,64,65] mesoporous carbon, [66,67] graphene, [68] high-quality graphene, [69] carbon nanotubes, [70] carbon fibers, [71,72] polypyrrole, [73] etc., and its applications have been exploited in various fields, for instance, batteries, [74] supercapacitors (SCs), [75] electromagnetic wave absorption, [59,…”