| Silver gallium sulfide(AgGaS2) is a I -III-VI2 ternary compound semiconductor that Crystallizes in chalcopyrite structure (point group D2d-42m). It is transparent in a region from the visible to the infrared range(0.45-13?m) and has a fitful birefringence and a large nonlinear coefficient. AgGaS2 crystal can be made to be octonary device, difference-frequence device and parametric oscillator, and laser sources of different frequences in 1.8-11?m band can be provided. So AgGaS2 crystal is of good qualities and broad prospect in use.In this paper, AgGaS2 polycrystal was synthesized by two-zone vapor-transport ing and temperature-oscillating method (TVTM) with high pure elements Silver(Ag),Gallium(Ga),and Sulfur(S).In the synthetic procedure, S vapor was transported from lower temperature zone to the higher where S reacted with Ag and Ga to get AgGaS2, and then AgGaS2 was temperature-oscillated many times between 1060? and 900?. By TVTM, it made the ampoule less crack rate and the material much better. X-ray diffraction showed that it was high-pure AgGaS2 polycrystal of single-phase and high-density. In crystal growth experiment, AgGaS2 crystal was growen in special quartz ampoule by crucible descending method (B-S method). The equipments were used, which consist of a two-zone vertical growth furnace whose temperature gradient is tunable, a descending device with decelerating rate of 1:2000, a controlling system of electy and a temperature testing system using thermal couples. Singlecrystal with 15mm in diameter and 30mm in length was growen. The temperature gradient was 40?/cm and the growing speed was 10mm/day. Analysis of X-ray diffraction showed the crystal is AgGaS2 single crystal. The infrared transmittance of the crystal between 2-10?m is 49% and absorption coeffiecient is 0.74cm-1.
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