Defect studies by X-ray diffraction, electrical and optical properties of layer type tungsten mixed molybdenum sulphoselenide

摘要: Abstract Layer type tungsten mixed molybdenum sulphoselenide, Mo 0.5 W S x Se 2− (0≤ ≤2) starting from ternary 2 compound and by substituting selenium with sulphur ended which is also a compound, have been prepared characterized. X-ray diffraction studies showed that all the compounds possess 2H–MoS structure small change in - c -parameters. line profile analysis has used to calculate microstructural defect parameters of these compounds. It rich relatively crystallite size ( P ), high r.m.s. strain (〈 e 〉) 1/2 dislocation density ρ dis ). However, SSe large , low Fractional interlayer spacing proportion planes affected defects increased increasing contents it was maximum case . Radial distribution function (RDF) interatomic distances, 2.80, 3.40 3.86 A corresponds metal–chalcogen, for intra chalcogen–chalcogen bonding, respectively. The coupling constants corresponding other higher pair atoms calculated. Room temperature thermoelectric power experiments variation conductivity confirmed their p-type semiconducting behaviour. Attempts made correlate crystallites. band gaps are range 1.20 eV 1.07