Growth and characterization of US and doped CdS single crystals

US and phosphorus, silicon and selenium doped US have been grown by physical vapour technique. The quartz ampoule used for the growth is designed according to Schieber's (Technology of crystal growth, ULCA, Extension course Engineering, 1974, p. 881) conditions. The growth temperature is 915degreesC with undercooling of 25degreesC. For better transport the starting material is prepared as needle-like polycrystalline crystal under high temperature gradient. The crystals of cm, size are formed like boule. The growth pattern of different boule is analysed by taking AFM photograph and growth observed in both polar directions. The Hall mobility is measured for the pure and doped CdS. At room temperature mobility is found to be 335 (cm(2)/V s) and the dislocation density to be 5 x 10(6) cm(-2). From photocurrent spectra the optical band gap is found for CdS, CdS:P, CdS:Se, and CdS:Si using Ex(A) exciton peak. (C) 2002 Elsevier Science B.V. All rights reserved.