SYNTHESIS AND GROWTH OF LARGE STOICHIOMETRIC SINGLE-CRYSTALS OF COPPER INDIUM DISELENIDE BY HORIZONTAL VARYING GRADIENT ZONE FREEZE TECHNIQUE

A new method to grow large single crystals with stoichiometry close to 1:1.2 of CuInSe2, an important member of the I-III-VI2 family of chal copyrite semiconductors for optoelectronic device applications, is des cribed. This is called the horizontal varying gradient zone freeze tec hnique and consists of the selenization in the liquid phase of stoichi ometric Cu and In and later solidification under programmed varying gr adient in a fully automated multiple zone horizontal furnace. All ingo ts obtained with Se pressure between 15 and 1760 mm of Hg were single phase having chalcopyrite structure and p-type conductivity. X-ray, DT A, optical and electrical characterizations of the samples taken from different parts of the ingots were made. From energy dispersive spectr oscopy it is found that the samples of the ingot obtained with Se pres sure at 836 mm of Hg were much closer to the ideal stoichiometry 1:1:2 .