Synthesis of Cu2ZnSnS4 (CZTS) absorber by rapid thermal processing (RTP) sulfurization of stacked metallic precursor films for solar cell applications

Abstract

Cu2ZnSnS4 (CZTS) absorbers have been grown on Mo-coated glass substrates by the rapid thermal processing (RTP) sulfurization of stacked metallic precursor (CZT) films at different annealing temperatures ranging from 500 to 580 degrees C for 5 min in sulfur atmosphere. The effects of sulfurization temperature on the structural, morphological, chemical, and optical properties of the CZTS absorbers have been investigated. XRD and Raman studies reveal that the as-deposited stacked metallic precursor films consist of metal elements such as Zn, Sn and binary alloys such as Cu6Sn5, Cu3Sn and CuZn. The sulfurized CZTS absorber films have single phase polycrystalline kesterite crystal structure with dense morphology. At 580 degrees C the CZT metallic precursor film is fully sulfurized with Zn-rich and Sn-poor composition, and its bandgap energy is found to be 1.50 eV. The solar cell fabricated with the CZTS absorber grown at an optimized sulfurization temperature of 580 degrees C shows a conversion efficiency of similar to 5% for a 0.44 cm(2) area with V-oc=561 mV, J(sc)=18.4 mA/cm(2), and FF=48.2. (C) 2013 Elsevier B.V. All rights reserved.