Effect of Annealing Temperature on the Thermoelectric Properties of the Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^ Thin Films Prepared by Radio-Frequency Sputtering

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2013-05, Vol.44 (5), p.2339
• Main Authors: Lin, Huey-jiuan, Kang, Kai-jyun, Hwang, Jenn-dong, Chu, Hsu-shen, Huang, Hong-hsin, Wang, Moo-chin
• Format: Article
• Language: English
• Subjects: Annealing; Crystal structure; Morphology; Substrates; Temperature; Thin films
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-012-1587-5

The effect of annealing temperature on the crystallinity, thermoelectric properties, and surface morphology of the Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^ thin films prepared on SiO2/Si substrate by radio-frequency (RF) magnetron sputtering was investigated using X-ray diffraction (XRD), the four-point probe method, and scanning electron microscopy (SEM). XRD results show that the crystallite structure of the Bi^sub x^Sb^sub 2â[euro]"x^Te^sub 3^ thin films belong to Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^. When the Bi^sub x^Sb^sub 2â[euro]"x^Te^sub 3^ thin films were annealed between 423Â K and 523Â K (150Â °C and 250Â °C) for 10Â minutes, the crystallinity of the thin films continuously increases with the temperature increase. In addition, the (015) reflection plane as the preferred orientation and the oxidation compound of Bi^sub 3.73^Sb^sub 1.5^O3 first appeared when the Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^ thin films were annealed at 523Â K (250Â °C) for 10Â minutes. An activation energy of 51.66Â kJ/mol for crystallite growth of Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^ thin films annealed between 423Â K and 523Â K (150Â °C and 250Â °C) for 10Â minutes was obtained. The resistivity was 2.69Â Ã--Â 10^sup 2^ and 5.93Â Ã--Â 10Â [mu]Ω·m, respectively, for the as-deposited Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^ thin films and annealed at 523Â K (250Â °C) for 10Â minutes. The maximum values of the Seebeck coefficient and power factor were 256.5Â [mu]V/K and 1.12Â Ã--Â 10^sup 3^Â [mu]W/m·K^sup 2^, respectively, for the Bi^sub 0.5^Sb^sub 1.5^Te^sub 3^ thin films annealing treatment at 523Â K (250Â °C) for 10Â minutes.[PUBLICATION ABSTRACT]