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采用闪蒸法在温度为473 K的玻璃基体上沉积了厚度为800 nm的N型Bi2(Te0.95Se0.05)3热电薄膜,并在373～573 K进行1 h的真空退火处理。利用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)分别对薄膜的物相结构和表面形貌进行分析。采用表面粗糙度测量仪测定薄膜厚度,薄膜的电阻率采用四探针法进行测量,采用温差电动势法在室温下对薄膜的Seebeck系数进行表征。沉积态薄膜表明了(015)衍射峰为最强峰,退火处理后最强衍射峰为(006);沉积态薄膜由许多纳米晶粒组成,晶粒大小分布较均匀,平均晶粒尺寸大约45 nm,退火处理后出现了斜方六面体的片状晶体结构。退火温度从373 K增加到473 K,薄膜的电阻率和Seebeck系数增加,激活能也随退火温度的增加而增大,退火温度从523 K增加到573 K,薄膜的电阻率和Seebeck系数都缓慢下降。从373～473 K,热电功率因子随退火温度的升高而单调增加,退火温度为473 K时,电阻率和Seebeck系数分别是2.7 mΩ.cm和-180μV.K-1,热电功率因子最大值为12μW.cmK-2。退火温度从523 K增加到573 K,热电功率因子的值逐渐下降。
An N type Bi2 (Te0.95Se0.05) 3 thermoelectric thin film with a thickness of 800 nm was deposited on a glass substrate with a temperature of 473 K by flash method and annealed at 373 ~ 573 K for 1 h. The phase structure and surface morphology of the films were analyzed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The film thickness was measured by the surface roughness measuring instrument. The resistivity of the film was measured by the four-probe method. The Seebeck coefficient of the film was characterized by the temperature difference emf method at room temperature. The deposited films show that the (015) diffraction peak is the strongest peak, and the strongest diffraction peak after annealing is (006). The as-deposited film is composed of many nanocrystalline grains with a uniform grain size distribution with an average grain size of about 45 nm, there was a lamellar crystal structure of rhombohedral after annealing treatment. The annealing temperature increases from 373 K to 473 K, and the resistivity and Seebeck coefficient increase. The activation energy also increases with the increase of annealing temperature. The annealing temperature increases from 523 K to 573 K. The resistivity and Seebeck coefficient of the films are slow decline. From 373 to 473 K, the thermoelectric power factor monotonically increases with the increase of the annealing temperature. When the annealing temperature is 473 K, the resistivity and Seebeck coefficient are 2.7 mΩ · cm and -180 μV · K-1 respectively. The maximum value of the thermoelectric power factor 12 μW · cm K-2. The annealing temperature increases from 523 K to 573 K, and the value of the thermoelectric power factor gradually decreases.