Electronic structure of transition metal dichalcogenides monolayers 1H-MX2 (M = Mo, W; X = S, Se, Te) from ab-initio theory: new direct band gap semiconductors

摘要: We report first principles calculations of the electronic structure monolayer 1H-MX2 (M = Mo, W; X S, Se, Te), using pseudopotential and numerical atomic orbital basis sets based methods within local density approximation. Electronic band states found that around Fermi energy are mainly due to metal d states. From partial we find a strong hybridisation between chalcogen p below energy. All studied compounds in this work have emerged as new direct gap semiconductors. The is decrease one goes from sulphides tellurides both Mo W. Reducing slab thickness systematically bulk monolayers causes blue shift energies, resulting tunability gap. magnitudes energies be 1.14 eV, 1.16 0.78 0.64, 0.57 eV 0.37 for MoS2, WS2, MoSe2, WSe2, MoTe2 WTe2, respectively, go phase (indirect gap) limit (direct gap). This transitions indirect make these materials potential candidates fabrication optoelectronic devices.