快速退火对磁控溅射制备Bi/Te多层膜热电性能的影响

Effect of Rapid Thermal Annealing on Thermoelectric Properties of Bi/Te Multilayer Films Deposited by Magnetron Sputtering

采用磁控溅射法在玻璃衬底上室温沉积Bi/Te多层膜,并在常压氮气保护下进行快速退火处理。研究退火温度和时间对薄膜的显微结构、物相组成和热电性能的影响。结果表明：随退火时间的延长样品中依次出现片状晶粒的成核、定向生长和横向堆叠等结构的演变特征,使晶粒沿横向逐渐增厚,且退火温度越高,结构演变速率越快。退火样品以Bi2Te3为主相,350400℃退火使薄膜表层生成少量Bi-Te氧化物。随退火时间的延长,与晶粒堆叠厚度相关的量子化效应显现,使薄膜的热电性能出现明显的振荡现象。在350℃退火1117 min的薄膜,可获得稳定的高功率因数,最大值为21.91μW/（K2·cm）。

The periodic Bi/Te multilayer film was deposited on a glass substrate via magnetron sputtering at room temperature, and a rapid thermal annealing treatment was carried out under N2 atmosphere. The effects of annealing temperature and time on the microstructure, phase composition and thermoelectric properties of Bi/Te multilayer films were investigated. The results show that lots of lamellar crystals appear sequentially as the textures of crystal nucleus, orientation growth and stack layer in Bi/Te multilayer films during post-thermal treatment, leading to a gradual increase of in-plane thickness of stack layer with the elapse of annealing time. Also, the thickness of stack layer can be increased with elevated annealing temperature. Bi2Te3 is the major compound phase in the samples annealed at different temperatures, and a small amount of Bi-Te oxide appears on the surface layer of samples annealed at 350-400 °C. The quantum confinement effect is related to the thickness of stack layer when annealing time increases, giving rise to an obvious oscillations phenomenon of film thermoelectric properties. A stable high power factor can be obtained in the sample annealed at 350 °C for 11-17 min, and the maximum power factor value is 21.91 μW/（K2·cm）.