Structural, optical and electrical properties of Bi2−xMnxTe3 thin films

• Published in: Journal of materials science. Materials in electronics 2022-01, Vol.33 (1), p.158-166
• Main Authors: Hadia, N. M. A., Mohamed, S. H., Mohamed, W. S., Alzaid, Meshal, Khan, Mohd Taukeer, Awad, M. A.
• Format: Article
• Language: English
• Subjects: Bismuth tellurides; Carrier density; Characterization and Evaluation of Materials; Chemistry and Materials Science; Doped films; Doping; Electrical properties; Ellipsometry; Manganese; Materials Science; Optical and Electronic Materials; Optical properties; Surface roughness; Thin films
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-07281-8

Undoped and Mn doped Bi 2 Te 3 ( x = 0, 0.05 and 0.10 at%) thin films were prepared via thermal evaporation method from their bulk alloys. X-ray diffraction revealed the presence of hexagonal Bi 2 Te 3 crystalline phase only in all undoped and Mn doped films. EDAX quantitative analysis revealed that the effective Mn doping is close to that of the intended. SEM observations revealed uniform spherical grains for all films with more porous and less dense grains at higher Mn content. The increase in Mn doping ratio to x = 0.1 decreases the carrier density and the carrier type changes to the P-type conduction. The transmittance values increased with Mn doping whereas the reflectance decreased. The optical band gap increased from 0.25 to 0.39 eV. Two layer-model was successfully used to simulate the ellipsometry measurements. The main layer was described by a combined contribution of Drude and Lorentz models. The thickness, the optical constants, and the surface roughness of the undoped and Mn doped films were extracted from the ellipsometry measurements. Upon Mn doping, the PL was quenched.