Computational Search for Two-Dimensional MX2 Semiconductors with Possible High Electron Mobility at Room Temperature

Abstract

Neither of the two typical two-dimensional materials, graphene and single layer MoS2, are good enough for developing semiconductor logical devices. We calculated the electron mobility of 14 two-dimensional semiconductors with composition of MX2, where M (=Mo, W, Sn, Hf, Zr and Pt) are transition metals, and Xs are S, Se and Te. We approximated the electron phonon scattering matrix by deformation potentials, within which long wave longitudinal acoustical and optical phonon scatterings were included. Piezoelectric scattering in the compounds without inversion symmetry is also taken into account. We found that out of the 14 compounds, WS2, PtS2 and PtSe2 are promising for logical devices regarding the possible high electron mobility and finite band gap. Especially, the phonon limited electron mobility in PtSe2 reaches about 4000 cm2·V-1·s-1 at room temperature, which is the highest among the compounds with an indirect bandgap of about 1.25 eV under the local density approximation. Our results can be the first guide for experiments to synthesize better two-dimensional materials for future semiconductor devices.

Quantum confinement-induced semimetal-to-semiconductor evolution in large-area ultra-thin PtSe2 films grown at 400 °C

“…Calibration of Green's function with screened Coulomb interaction (GW) is utilized to predict the quantitative values of the bandgap energy. The bandgap opening in few-layer PtSe 2 , reported in other works, 7,8,14,[19][20][21][22][23] is shown to depend strongly on the simulation framework, with a progressive increase in the PtSe 2 energy gap when considering density function theory (DFT), to DFT with the addition of vdW interactions, and finally to DFT with vdW interactions and screened Coulomb interaction. The Bohr radius provides an estimation of when the quantum effects modify the band structure.…”

Electrical devices from top-down structured platinum diselenide films

“…Recently, the electronic structure and properties of these materials have been theoretically evaluated and, as a consequence of their promising characteristics, they have been proposed for use in electronic device applications. [27,28] Platinum diselenide (PtSe 2 ) is one such group-10 TMD which is known to be a semimetal in bulk form with zero bandgap. [29] Theoretical calculations suggested a transition from semimetal to semiconductor with reduced PtSe 2 thickness [27,30] and it was shown experimentally by Wang et al that monolayer PtSe 2 has a bandgap of ~1.2 eV.…”

Facile Synthesis of Single Crystal PtSe2 Nanosheets for Nanoscale Electronics

“…The actual potential difference is not accurate because it is strongly affected by the surface adsorbates . Nevertheless, the difference potentials reveal that the work function of PtSe 2 is higher than that of MoS 2 , and the energy‐band diagram could be sketched as shown in Figure f, where the band gap of MoS 2 and PtSe 2 are 1.8 and 1.2 eV, respectively. The thickness‐dependent properties should be important for the electronic performance of 2D materials in general.…”