Effect of solvents on morphological and electrical properties of Bi₂Te₃ nanostructures

In present work, we investigated the effect of different solvents and concentration of PVP surfactant on morphological and electrical properties of Bi₂Te₃ nanostructures. As water has high dielectric constant and high surface tension, which will enhance the mobility of charge carriers, and electrical conductivity of the material. High concentration of PVP provide better dispersion stability and prevent agglomeration and produces defects like stacking fault and grain boundaries. The Bi₂Te₃ nanostructures were prepared with different solvent via solvothermal method. These have rhombohedral crystal structure with space group R \(\overline{3 }\) $\overline{3}$  m as examined by XRD. Different morphology of nanoflakes, hexagonal nanoplates, and nanoparticles were observed by FESEM. The density measurement and FESEM confirmed the porous structure. The valance states and binding energy was determined by XPS study. The carrier concentration and mobility were obtained by Hall effect. Carrier concentration of 7 × 10¹⁹ cm⁻³ to 11.28 × 10¹⁹ cm⁻³ were obtained at room temperature. The band gap energy of ~ 0.28 eV was calculated by Tauc plot. The maximum \(\sigma\) $\sigma$ of 1.2 × 10⁵ S/m at 480 K is obtained for sample prepared with water as solvent.