Enhanced electrical properties of stoichiometric Bi0.5Sb1.5Te3 film with high-crystallinity via layer-by-layer in-situ Growth. (March 2017)

• Record Type: Journal Article
• Authors: Mu, Xin; Zhou, Hongyu; He, Danqi; Zhao, Wenyu; Wei, Ping; Zhu, Wanting; Nie, Xiaolei; Liu, Huijun; Zhang, Qingjie
• Is Part Of: Nano energy. Volume 33(2017:Mar.)
• Page Start: 55
• Page End: 64
• Publication Date: 2017-03
• Subjects: Thermoelectric material -- Bi2Te3-based films -- Electrical transport properties -- Preferential orientation -- Layer-by-layer in-situ growth; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2017.01.013
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: The preparation of high-performance Bi2 Te3 -based films is vitally important for the miniaturization of Bi2 Te3 thermoelectric (TE) device. Herein, a series of stoichiometric Bi0.5 Sb1.5 Te3 films with different preferential orientations have been fabricated through in-situ crystallization during the co-sputtering process. We discover that the preferential orientation was transformed from (01 1 ̅ 5) to (10 1 ̅ 10 ) to (000 l ) orientation with increasing the substrate temperature. The (000 l )-oriented films exhibit the best electrical transport properties, which the maximum electrical conductivity of 8.0×10 4 S·m -1 and power factor of 3.8 mW K -2 ·m -1 are much more than those of the bulk material. The excellent properties are attributed to the high-crystallinity, well-controlled preferential orientation, and minimized compositional deviation. A layer-by-layer in-situ growth model is proposed to understand the formation mechanism of the (000 l )-oriented films. Our work demonstrates that the electrical transport performance of Bi2 Te3 -based films can be remarkably improved through finely controlling the crystallinity and preferential orientation under the condition of stoichiometric composition. Graphical abstract: Highlights: Stoichiometric Bi0.5 Sb1.5 Te3 films are fabricated by in-situ crystallization. The (000 l ) orientations and high crystallinity of these films have been realized. Three parameters of electrical properties ( μ, σ, α ) are simultaneously increased. The relationship between the electric properties and orientations are calculated. A layer-by-layer in-situ growth model is proposed for (000 l )-oriented films.