Raman Spectroscopy of Two-Dimensional Bi2TexSe3 − x Platelets Produced by Solvothermal Method

Materials

Jian Yuan²  Meng Zhao¹  Wengzhi Yu²  Yao Lu²  Caiyun Chen²  Meng Xu²  Shaojuan Li²  Kian Ping Loh¹  Qiaoliang Bao¹ 

[1]Department of Chemistry, and Graphene Research Centre, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore

[2] E-Mails:

[3]Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, China

[4] E-Mails:

关键词: bismuth chalcogenide;    solvothermal;    stoichiometric ratio;    Raman spectroscopy;    infrared active;   

DOI  :  10.3390/ma8085007

来源: mdpi

【 摘 要 】

In this paper, we report a facile solvothermal method to produce both binary and ternary compounds of bismuth chalcogenides in the form of Bi₂Te_xSe_{3 − x}. The crystal morphology in terms of geometry and thickness as well as the stoichiometric ratio can be well controlled, which offers the opportunities to systematically investigate the relationship between microstructure and phonon scattering by Raman spectroscopy. Raman spectra of four compounds, i.e., Bi₂Se₃, Bi₂Se₂Te, Bi₂SeTe₂ and Bi₂Te₃, were collected at four different excitation photon energies (2.54, 2.41, 1.96, and 1.58 eV). It is found that the vibrational modes are shifted to higher frequency with more Se incorporation towards the replacement of Te. The dependence of Raman vibrational modes on excitation photon energy was investigated. As the excitation photon energy increases, three Raman vibrational modes (A_1g¹, E_g² and A_1g²) of the as-produced compounds move to low frequency. Three Infrared-active (IR-active) modes were observed in thin topological insulators (TIs) crystals.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.