Effect of (Sm, In) Doping on the Electrical and Thermal Properties of Sb2Te3 Microstructures

Doped Sb2Te3 narrow-band-gap semiconductors have been attracting considerable attention for different electronic and thermoelectric applications. Trivalent samarium (Sm)-and indium (In)-doped Sb2Te3 microstructures have been synthesized by the economical solvothermal method. Powder X-ray diffraction (PXRD) was used to verify the synthesis of single-phase doped and undoped Sb2Te3 and doping of Sm and In within the crystal lattice of Sb2Te3. Further, the morphology, structure elucidation, and stability have been investigated systematically by scanning electron microscopy (SEM), Raman analysis, and thermogravimetric analysis (TGA). These analyses verified the successful synthesis of hexagonal undoped Sb2Te3 (AT) and (Sm, In)-doped Sb2Te3 (SAT, IAT) microstructures. Moreover, the comparison of dielectric parameters, including dielectric constant, dielectric loss, and tan loss of AT, SAT, and IAT, was done in detail. An increment in the electrical conductivities, both AC and DC, from 1.92 x 10-4 to 4.9 x 10-3 omega-1 m-1 and a decrease in thermal conductivity (0.68-0.60 W m-1 K-1) were observed due to the doping by trivalent (Sm, In) dopants. According to our best knowledge, the synthesis and dielectric properties of (Sm, In)-doped and undoped Sb2Te3 in comparison with their electrical properties and thermal conductivity have not been reported earlier. This implies that appropriate doping with (Sm, In) in Sb2Te3 is promising to enhance the electronic and thermoelectric behavior.