Crystalline bismuth telluride nanoparticles grown by a magnetically assisted physical method. (15th November 2016)

• Record Type: Journal Article
• Authors: Park, Jong Whan; Nguyen, Son Thanh; Luan, Yange; Noh, Jin-Seo
• Is Part Of: Materials & design. Volume 110(2016)
• Page Start: 449
• Page End: 455
• Publication Date: 2016-11-15
• Subjects: Bi2Te3 nanoparticles -- Physical method -- Co-sputtering -- Magnetic interaction; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.08.014
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: A magnetically assisted physical method was developed to synthesize crystalline bismuth telluride (Bi2 Te3 ) nanoparticles. This method takes advantage of co-sputtering from Bi2 Te3 and cobalt (Co) targets at elevated temperatures. Well-faceted polygonal or pyramidal nanoparticles were obtained from co-sputtering at a substrate temperature above 200 °C. The nanoparticles were analyzed to have a Bi to Te atomic ratio of 2 to 3, which represents the stoichiometric composition of Bi2 Te3, without any detectable Co. The lateral size of Bi2 Te3 nanoparticles generally increased in the range of 50–160 nm and their facet structure was better developed as the growth temperature increased. Electron microscopy studies revealed that the Bi2 Te3 nanoparticles were distributed on the surface of a growing Bi2 Te3 thin film. Both the nanoparticles and the thin film were proven to be highly crystalline by cross-sectional TEM and selected-area electron diffraction patterns. A series of physical mechanisms were proposed to account for this unique growth technique. Graphical abstract: Highlights: Well-faceted Bi2 Te3 nanoparticles were synthesized by a co-sputtering technique at above 200 °C. Diamagnetic Bi2 Te3 and ferromagnetic cobalt targets were used for the co-sputtering. The size of Bi2 Te3 nanoparticles could be controlled by adjusting relative powers and growth temperature and time. A growth mechanism based on diamagnetic repulsion and cobalt kick-off was proposed.