Optical analysis for few TMDC materials

Bulletin of Materials Science

关键词: Transition metal diachalcogenides;    optical parameters;    bandgap.;   

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

The transition metal dichalcogenides possess layered structure of Se-M-Se (M = Nb, Mo, Ta and W) sandwich interact with each other by van der Waal forces and can also provide sites for intercalation. Because of their technological importance, lubricants, catalysts, battery cathodes and electrodes in the photoelectrochemical solar cells, much attention has gone in the studies of growth of these materials in crystalline and nanocrystalline forms. In the present work we report the growth of NbSe2, MoSe2, TaSe2 and WSe2 single crystals and determine the optical bandgap using optical absorption. The optical absorption of as-grown crystals has been measured at room temperature near the fundamental absorption edge. Both direct and indirect transitions are involved in the absorption process. The indirect transition was found to be allowed with two phonons involved in the process. The direct and indirect energy gaps and phonon energies for all crystals have been estimated. The results obtained are discussed in detail.

【 授权许可】

CC BY