Mat. Res. Bull., Vol. 15, pp. 1367-1370, 1980. Printed in the USA. 0025-5408/80/I01367-04502.00/0 Copyright (e) 1980 Pergamon Press, Ltd. PHASE EQUILIBRIUM IN THE CdSe-TISe SYSTEM A. Borshchevsky and R. S. Feigelson Center for Materials Research Stanford University Stanford, California 94305 (Received April 30, 1980; Refereed) ABSTRACT In the Cd-TI-Se system the CdSe-TISe binary join was studied for the first time in detail by DTA, microprobe, x-ray, and microstructure analysis. The phase diagram shows that the section is a classic de- generative eutectic system with no compound formation. The last three decades saw an intensive search for new semiconductor and optical materials to satisfy many different device applications. A large num- ber of new compounds were discovered, described, and proposed for various applications, and several books were written on this subject including refer- ences (1-3). Unfortunately, the details for the materials preparation of many of these compositions were not fully described. Often this situation creates some difficulty in repeating and verifying the published results, and once in a while the published results cannot be repeated at all. The existence of a new class of semiconductor compounds of the type CdTIX 2 (X = X, Se, Te) was claimed about ten years ago (4,5). The crystal structure of these compounds was described, and the electronic, photoelectric, and ther- mal properties studied. Because of our interest in uniaxial materials with infrared optical transparency, an attempt was made to synthesize these com- pounds, with most emphasis being placed on CdTISe 2. Guseinov et al. (4) claimed that the compound CdTISe 2 could be synthesized from a stoichiometric melt or from solution (the composition was not indicated). In our experiments, CdTiSe 2 synthesis was attempted by melting together the elements in stoichiometric propartions. The temperature of the furnace was raised slowly up to 450°C, held there 5-10 hours, then raised to 1000°C. After several hours at this temperature it was lowered by the natural cooling rate of the furnace. The ingots obtained were black, dense and polycrystalline. The microstructure of these samples revealed two phases (Fig. lc), the composi- tions of which, as determined by microprobe analysis, corresponded closely to CdSe and TiSe. 1367