Crystal structure and band gap measurements of Vanadium diselenide single crystals

Single crystals of layered single crystals of vanadiumdiselenide were grown by chemical vapour transport technique using iodine as transporting agent The stoichometry of the grown crystal was ascertained by EDAX analysis of as grown crystals. The structural characterization was accomplished by XRPD. The optical band gap of vanadium diselenide single crystals were determined from the analysis of the absorption spectrum near the fundamental absorption edge at room temperature using light parallel to c-axis incident normally on the basal plane. 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 indirect and direct band gap for VSe2 single crystals are 1.4 eV and 1.46 eV respectively.