Physical properties of Bi2 (Te, Se)3 and Bi2Se1.2Te1.8 prepared using solid-state microwave synthesis

Bi2(Te, Se)3 and Bi2Se1.2Te1.8 bulk products were synthesised using standard solid-state microwave synthesis. The Bi2(Te, Se)3 and Bi2Se1.2Te1.8 were then deposited thermally onto glass substrates at a pressure of 10− 6 Torr. The structure of the samples was analysed using X-ray diffraction (XRD), and the powders and thin films were observed to be polycrystalline and rhombohedral in structure. The surface morphology of the samples was determined using scanning electron microscopy (SEM). From the measurements of optical properties, the energy gap values for the Bi2Te3, Bi2Se3, and Bi2Se1.2Te1.8 thin films were 0.43, 0.73, and 0.65 eV, respectively.

► Bi2(Te, Se)3 and Bi2Se1.2Te1.8 bulk products have been synthesised by solid-state microwave procedures.
► The bulk products reveal a non-uniform distribution of grain and are characterised by some void spaces.
► The corresponding thin films were deposited via thermal evaporation of the bulk products.
► The optical band gap Eg increased with increasing Se content.