Enhancement in thermoelectric figure of merit of bismuth telluride system due to tin and selenium co-doping. (1st June 2021)

• Record Type: Journal Article
• Authors: Hegde, Ganesh Shridhar; Prabhu, A.N.; Rao, Ashok; Chattopadhyay, M.K.
• Is Part Of: Materials science in semiconductor processing. Volume 127(2021)
• Publication Date: 2021-06-01
• Subjects: Semiconductor -- Solid-state reaction -- X-ray diffraction -- Thermoelectric material -- Thermal conductivity -- Thermoelectric figure of merit; Semiconductors -- Periodicals; Integrated circuits -- Materials -- Periodicals; Semiconducteurs -- Périodiques; Circuits intégrés -- Matériaux -- Périodiques; Electronic journals; 621.38152
• DOI: 10.1016/j.mssp.2020.105645
• Languages: English
• ISSNs: 1369-8001

Abstract

Abstract: Thermoelectric performance of tin and selenium co-doped bismuth telluride in the temperature range 10–300 K, prepared by solid-state reaction is reported in the current work. The powder X-ray diffraction study reveals hexagonal crystal structure with R 3 ‾ m space group . Energy dispersive X-ray analysis confirms elemental composition within the experimental limits and Field Emission Scanning Electron Microscopy (FESEM) shows uniform grain density and porosity on the surface of the pristine and doped samples. The electrical resistivity shows quasi degenerate semiconducting behavior and the temperature dependent Seebeck coefficient confirms n -type semiconducting nature of the pristine as well as doped samples. The carrier concentration and carrier mobility are of the order 10 25 /m 3 and 10 −4 m 2 /Vs respectively. A significant reduction in the thermal conductivity has been found in the (Bi0.98 Sn0.02 )2 Te2.7 Se0.3 compound, leading to an enhancement in the power factor ( PF ) and thermoelectric figure of merit ( ZT ) by 3.2 and 13.5 times respectively as compared to that of the pristine sample Bi2 Te3 at 300 K. The highest ZT value of about 0.27 is achieved for (Bi0.98 Sn0.02 )2 Te2.7 Se0.3 at 300 K. Highlights: Tin and selenium co-doped bismuth telluride samples have hexagonal crystal structure with the space group R 3 ‾ m. Electrical resistivity has shown quasi - degenerate semiconducting behavior. Enhancement in Seebeck coefficient and substantial decrease in thermal conductivity has been observed with increasing doping concentration. The highest PF and ZT values are found to be 800 μ W/mK 2 and 0.27 at 300 K respectively. The present material can be a potential candidate for near room temperature Peltier cooling applications.