Influence of precursor sulfur content on film formation and the properties of sulfurized Cu2ZnSnS4 thin films for solar cells

Abstract

This is the Cu2ZnSnS4 (CZTS) films were fabricated on glass substrates by sputtering using compound material targets. The fabrication method combines the deposition of metallic precursors and the sulfurization annealing process using S vapor. The optimal precursor sequence for CZTS growth was Cu/SnS/ZnS/Mo. To optimize the composition and the thickness of CZTS, the thickness of Cu layer and precursor was varied. The best cell had an area of 0.185 cm2, Cu/(Zn + Sn) = 0.89, Zn/Sn = 1.04, and S/(metal) = 1.13 and showed an open-circuit voltage (VOC) of 0.66 V, a short-circuit current (JSC) of 13.60 mA cm-2, a fill factor of 43.14% and a conversion efficiency of 3.84%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.