Structural, Morphological and Optical Characterization of Cobalt Diselenide Grown by Direct Vapor Transport (DVT) Method

Authors Darshan. J. Jadav, S.M. Vyas , A.M. Vora

Department of Physics, University School of Science, Gujarat University, Navarangpura, Ahmedabad – 380 009, Gujarat, India

Issue Volume 14, Year 2022, Number 5
Dates Received 03 August 2022; revised manuscript received 24 October 2022; published online 28 October 2022
Citation Darshan. J. Jadav, S.M. Vyas, A.M. Vora, J. Nano- Electron. Phys. 14 No 5, 05001 (2022)
PACS Number(s) 78.67. – n, 81.07. – b
Keywords 2D materials, TMDC, Cobalt diselenide, DVT technique, HRTEM-SAED.

Enormous research and many noteworthy innovations have been done using Transition Metal Dichalcogenides (TMDCs) over the years. This class of layered semiconductor materials has found a strong foothold in the realm of device making due to theirs many versatile properties. The tunable band gap, accompanied with remarkable photonic and electronic properties, are a few of the striking features of these materials. They follow the 'MX2' type of arrangement with van der Waals forces holding the interlayers, where M (Mo, Nb, Re, Hf etc.) symbolizes a transition metal and X (Se, S or Te, etc.) is a chalcogen atom. Among the family, cobalt is used as a dopant to perk up the properties of many compounds. The focus of the work is to grow cobalt diselenide (CoSe2) by Direct Vapor Transport (DVT) method using a custom made dual-zone furnace. XRD, HRTEM-SAED, SEM-EDX and UV-VIS-NIR spectroscopy are utilized to identify their structural, morphological and optical properties. XRD and SAED results confirm the polycrystalline nature of the sample prepared; also, the results are consistent with previously reported works. SEM and HRTEM depict the surface morphology and layered structure of the prepared sample. Also, EDX confirms the stoichiometry, purity and homogeneity of the prepared sample. The direct and indirect band gaps obtained using UV-VIS-NIR spectroscopy are 3.303 eV and 3.046 eV, respectively.

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