Growth and characterization of LiInS2 single crystals

Bulk LiInS2 single crystals were grown using the Bridgman-Stockbarger technique. The crystals were characterized in composition, structure and defects. The composition was determined both in average and local versions, the latter was carried out using the unique differential dissolution technique. For all crystals a departure from ideal LiInS2 stoichiometry, especially for cations, was detected. In the optical absorption spectra a strong band at 360 nm which disappears after annealing in S-2 vapor was, with a high probability, related to sulfur vacancies V-S: their oscillator strength is f greater than or equal to 1.3*10(-4). The blue photoluminescence in all crystals is likely to be due to In-Li antisite defect with an energy level 0.62 eV below the conduction band. The universal values of forbidden band gap, E-g are 3.72 and 3.57 eV at 80 and 300 K, respectively, for all crystals studied indicating the similar character of dominant bonds. (C) 2000 Elsevier Science B.V. All rights reserved.