A crystal growth furnace with new structure was designed based on a conventional vertical resistance-wound tubular two-temperature-zone furnace in order to meet the requirements of growing high-quality AgGaS2 single crystals. Large temperature gradients of 25-30 degrees C/cm at the growth interface and stable thermal profile were obtained. Integral and crack-free AgGaS2 single crystals with fewer defects were grown successfully and reproducibly in the furnace mentioned above. A new cleavage face (101) was observed in the as-grown AgGaS2 crystal. The crystal was characterized by using XRD and IR transmission microscopy. It is found that multiple diffraction peaks of the {101} faces are evident, and that IR transmittance is above 60%. The results show not only that the modified furnace is a new promising furnace for the growth of AgGaS2 single crystals, but also that the quality of the grown crystal is good. (c) 2006 Elsevier B.V. All rights reserved.