Raman scattering investigation of Bi 2Te 3 hexagonal nanoplates prepared by a solvothermal process in the absence of NaOH

• Published in: Journal of alloys and compounds Vol. 509; no. 16; pp. 5147 - 5151
• Main Authors: Liang, Yujie, Wang, Wenzhong, Zeng, Baoqing, Zhang, Guling, Huang, Jing, Li, Jin, Li, Te, Song, Yangyang, Zhang, Xiuyu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2011
• Subjects: Crystal growth; Crystal structure; Nanostructured materials; Optical spectroscopy; Thermoelectric materials; Crystal growth; Thermoelectric materials; Optical spectroscopy; Nanostructured materials; Crystal structure
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2011.02.015

► Hexagonal Bi 2Te 3 thin nanoplates were synthesized by a simple solvothermal method. ► Optical properties of the nanoplates were investigated by micro-Raman spectroscopy. ► Infrared (IR) active mode (A 1u) is greatly activated in Raman scattering spectrum. ► Infrared (IR) active mode (A 1u) shows up in Raman spectrum of hexagonal nanoplates. ► Raman spectrum clearly shows crystal symmetry breaking of hexagonal nanoplates. Hexagonal Bi 2Te 3 nanoplates were synthesized by a simple solvothermal process in the absence of NaOH. The composition, morphology and size of the as-prepared products were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Raman scattering optical properties of the as-prepared Bi 2Te 3 nanoplates were investigated by micro-Raman spectroscopy. The Raman spectrum shows that infrared (IR) active mode (A 1u), which must be odd parity and is Raman forbidden for bulk crystal due to its inversion symmetry, is greatly activated and shown up clearly in Raman scattering spectrum. We attribute the appearance of infrared active (A 1u) in Raman spectrum to crystal symmetry breaking of Bi 2Te 3 hexagonal nanoplates. The as-grown Bi 2Te 3 hexagonal nanoplates, exhibiting novel Raman optical properties compared with bulk crystals, may find potential applications in thermoelectric devices.