%0 Journal Article
%T Annealing Effect on the Thermoelectric Properties of Bi2Te3 Thin Films Prepared by Thermal Evaporation Method
%A Jyun-Min Lin
%A Ying-Chung Chen
%A Chi-Pi Lin
%J Journal of Nanomaterials
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/201017
%X Bismuth telluride-based compounds are known to be the best thermoelectric materials within room temperature region, which exhibit potential applications in cooler or power generation. In this paper, thermal evaporation processes were adopted to fabricate the n-type Bi2Te3 thin films on SiO2/Si substrates. The influence of thermal annealing on the microstructures and thermoelectric properties of Bi2Te3 thin films was investigated in temperature range 100¨C250¡ãC. The crystalline structures and morphologies were characterized by X-ray diffraction and field emission scanning electron microscope analyses. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature. The experimental results showed that both the Seebeck coefficient and power factor were enhanced as the annealing temperature increased. When the annealing temperature increased to 250¡ãC for 30£¿min, the Seebeck coefficient and power factor of n-type Bi2Te3-based thin films were found to be about £¿132.02£¿¦ÌV/K and 6.05£¿¦ÌW/cm¡¤K2, respectively. 1. Introduction Because the energy sources, such as petroleum, coal, and coal gas, will exhaust in the near future. Therefore, the problem of energy shortage and greenhouse effect become more and more serious, thus energy saving and reduction of the carbon emission become very important topics. Hence, the green technology is getting more and more attention. Thermoelectric (TE) effect is the simplest technology to convert the temperature difference to electrical energy. It generates electrical energy from the useless heat by thermoelectric effect. Thermoelectric materials can directly convert heat into electricity and vice versa. They have a lot of important applications, such as power generator [1] and cooler [2]. The performance of thermoelectric materials is decided by Seebeck coefficient, electrical conductivity, and thermal conductivity. The energy conversion efficiency of the thermoelectric materials is evaluated by the figure of merit , ( , Seebeck coefficient; , electrical conductivity; , absolute temperature; and , thermal conductivity) [3]. According to the formula, in order to obtain the excellent thermoelectric figure of merit, the materials must exhibit large Seebeck coefficient, high electrical conductivity, and low thermal conductivity. Among, the is defined as the power factor (PF). Currently, the bismuth telluride (Bi-Te) and antimony telluride- (Sb-Te-) based compounds are found to be the best thermoelectric materials within the room temperature region. Furthermore, Bi-Te- and Sb-Te-based thermoelectric
%U http://www.hindawi.com/journals/jnm/2013/201017/