Growth and thermoelectric study of CuInSe₂ single crystals

Ternary CuInSe₂ (CISe) chalcopyrite semiconductor single crystals are grown by chemical vapor transport technique. The elemental weight percentage of the as grown CISe single crystals obtain from the energy dispersive analysis of X-ray shows the crystals to be slightly rich in copper and selenium but slightly deficient in indium. The X-ray diffraction analysis of the as grown single crystals shows the sharp intense diffraction peaks confirmed the crystalline nature whereas the indexing of the peaks shows the tetragonal unit cell structure. The optical spectroscopic analysis of as-grown CISe single crystals shows sharp absorbance in the infra-red region. The direct optical band gap is 1.06 eV determined by Tauc's relation. The semiconducting nature of CISe single crystals are confirmed by Hall effect, Seebeck coefficient and resistivity versus temperature study. The obtained results are evaluated and discussed. Key words: CuInSe₂, single crystals, growth, structure, electrical transport. (author)