采用基于密度泛函理论的自洽赝势方法,计算了Bi—Te基热电材料不同化学配比下的电子结构。介绍了Bi2Te3材料的能带以及态密度,并计算了不同配比材料的载流子有效质量。计算结果显示:随着碲含量的增加,Bi—Te基热电材料从N型半导体向P型转变,在导电性质确定的情况下,塞贝克系数随着碲含量的增加而升高。
Energy band of Bi-Te based thermoelectric material was calculated using the density functional theory. Based on the comparison of band structures of Bi-Te materials with various compositon, the effect of Te content on thermoelectric properties was obtained. Calculation results showed that the lake Of Te widened the band gap, while the excess of Te narrowered the band gap. With the increase of Te content, electrical polarity of the material changed from N type to P type, and the value of Seebeck coefficient increased accordingly. Experimental measurements displayed high consistent with the calculation results.