Mechanistic aspects of preheating effects of precursors on characteristics of Cu_2ZnSnS_4 (CZTS) thin films and solar cells

摘要

CZTS thin films are fabricated using sol-gel method following sulfurization. The material properties of the CZTS films which are prepared under different preheating temperatures and times are systematically investigated. The TGA-DTA analysis shows that the sulfides begin to be oxidized and the CZTS nanoparticles would be formed when the preheating temperature is above 300 degrees C. Moreover, with increasing the preheating temperature and time, the crystallinity of the CZTS thin films becomes stronger firstly and then weaker. Morphological characterizations show that the CZTS thin films deliver the best crystallinity under the preheating temperature of 250 degrees C for 5 min. The E-g, resistivity, carrier concentration, and mobility of the CZTS thin films is 1.45 eV, 3.56 Omega.cm, 2.47 x 10(17) cm(-3), 7.12 cm(2).V-1.s(-1), respectively. The solar cells with the efficiency of 1.51% is successfully configured.