Proceedings Article | 5 March 2021
KEYWORDS: Modulation, Chemical species, Electronics engineering, Rhenium, Niobium, Doping, Crystals, Transition metals, Thermoelectric materials, Semiconductors
Recently, among the prototypical 2-dimensional transition metal dichalcogenide (TMDs) layered materials, WSe2 emerged as an excellent candidate and has gained tremendous research interest due to its uncanny Physico-chemical properties. The artificial engineering of zero-dimensional defects in TMDs demonstrated the bandgap tunability and a breakthrough to get the composition modulated atomically thin 2D semiconductors for the anticipated application. Herein, by using the first-principles method based density functional theory in conjunction with Boltzmann transport equation, we have investigated the stability, electronic band structures, and electronic transport coefficients of pristine and defective WSe2 monolayer with the introduction of vacancy, substitutional doping of Niobium (Nb) and Rhenium (Re) at the compositional proportion x (0 ≤ x ≤ 0:125), interstitial carbon (C) atoms and Frenkel defects at 300 K. Our results reveal that the introduction of vacancy defects induces localized states in the bandgap, Niobium (Nb) and Rhenium (Re) behave as p- and n-type dopants, interstitial carbon atom and Frenkel defects behave as iso-electronic dopants and they do not alter the intrinsic nature of the pristine monolayer WSe2. The calculated bandgap of monolayer pristine WSe2, vacancy defect, Nb-doped, Re-doped, C-adatom and Frenkel defect is 1.71 eV, 0.55 eV, 1.60 eV, 1.55 eV, 0.11 eV and 0.31 eV respectively. Furthermore, electrical conductivity (σ/Τ) is calculated as a function of chemical potential. At the studied chemical potential range, for the pristine monolayer WSe2 the achieved maximum electrical conductivity is 0.55×1020 Ω-1m-1s-1. In addition, for vacancy defect, Nb-doped, Re-doped, interstitial C-atom and Frenkel defect case, the achieved maximum electrical conductivities, are 0.3×1020 Ω-1m-1s-1, 0.12×1020 Ω -1m-1s-1, 0.17×1020 Ω-1m-1s-1, 0.16×1020 Ω -1-1s-1, 0.3×1020 Ω -1m-1s-1, and 0.11×1020 Ω -1m-1s-1, respectively. Our contribution provides insights to understand and ensure the rapid progress of the transport properties of 2D WSe2 based devices, with anticipated potential applications in next-generation integrated optoelectronics.
