Phase diagram of the Ag2SnS3-ZnS pseudobinary system for Ag2ZnSnS4 crystal growth

The phase equilibrium of the Ag2SnS3-ZnS pseudobinary system for the growth of Ag2ZnSnS4 (AZTS) crystals was investigated using the equilibration-quenching technique. The growth mechanism of AZTS follows the peritectic reaction liquid phase + ZnS phase. AZTS phase, which occurs at a composition of similar to 20 mol% ZnS and a temperature of approximately 700 degrees C. The AZTS polycrystalline sample was obtained from the stoichiometric melt growth. The kesterite structure of the AZTS sample without secondary phases was identified by a combination of X-ray diffraction and Raman spectroscopy measurements. The electron carrier concentration and conductivity, determined by the Hall effect measurement, were (3.0-6.3) x 10(15) cm(-3) and (5.6-9.2) x 10(-4) S/cm, respectively. The slightly Zn-rich and S-poor composition led to n-type conduction in the AZTS because of the dominant Zn antisites on Ag (Zn-Ag) and S vacancy (V-S) defects. Therefore, this study can make a significant contribution to the research and application of AZTS materials.