Comprehensive Structural, Chemical, and Optical Characterization of Cu<sub>2</sub>ZnSnS<sub>4</sub> Films on Kapton Using the Automated Successive Ionic Layer Adsorption and Reaction Method
Perla J. Vázquez-González,
Martha L. Paniagua-Chávez,
Lizette A. Zebadua-Chavarria,
Rafael Mota-Grajales,
C. A. Meza-Avendaño,
Enrique Campos-González,
A. Escobosa-Echavarría,
Yaoqiao Hu,
Aldo E. Pérez-Ramos,
Manuel-Matuz,
Carlos A. Hernández-Gutiérrez
Affiliations
Perla J. Vázquez-González
Tecnológico Nacional de México Campus Tuxtla, Carretera Panamericana Km 1080, Tuxtla Gutiérrez C.P. 29050, Mexico
Martha L. Paniagua-Chávez
Tecnológico Nacional de México Campus Tuxtla, Carretera Panamericana Km 1080, Tuxtla Gutiérrez C.P. 29050, Mexico
Lizette A. Zebadua-Chavarria
Programa de Nanociencias y Nanotecnología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional 2508, México City C.P. 07360, Mexico
Rafael Mota-Grajales
Tecnológico Nacional de México Campus Tuxtla, Carretera Panamericana Km 1080, Tuxtla Gutiérrez C.P. 29050, Mexico
C. A. Meza-Avendaño
Instituto de Investigación e Innovación en Energías Renovables, Universidad de Ciencias y Artes de Chiapas, Libramiento Norte 1150 Col. Lajas Maciel, Tuxtla Gutiérrez C.P. 29039, Mexico
Enrique Campos-González
Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Carretera México-Toluca s/n, La Marquesa, Ocoyoacac C.P. 52750, Mexico
A. Escobosa-Echavarría
Departamento Ingeniería Eléctrica—SEES, Cinvestav-IPN, México C.P. 07360, Mexico
Yaoqiao Hu
Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX 75080, USA
Aldo E. Pérez-Ramos
Tecnológico Nacional de Mexico/I.T. de Oaxaca, Calz. Tecnológico No. 125, Oaxaca C.P. 68030, Mexico
Manuel-Matuz
Tecnológico Nacional de México Campus Tapachula, Carretera a Puerto Madero Km. 2, Centro, Tapachula de Córdova y Ordoñez C.P. 30700, Mexico
Carlos A. Hernández-Gutiérrez
Tecnológico Nacional de México Campus Tuxtla, Carretera Panamericana Km 1080, Tuxtla Gutiérrez C.P. 29050, Mexico
This study provides a comprehensive structural, chemical, and optical characterization of CZTS thin films deposited on flexible Kapton substrates via the Successive Ionic Layer Adsorption and Reaction (SILAR) method. The investigation explored the effects of varying deposition cycles (40, 60, 70, and 80) and annealing treatments on the films. An X-ray diffraction (XRD) analysis demonstrated enhanced crystallinity and phase purity, particularly in films deposited with 70 cycles. These films exhibited a notable reduction in secondary phases in the as-deposited state, with further improvements observed after annealing at 400 °C and 450 °C in a sulfur atmosphere. A pole figure analysis indicates a decrease in texture disorder with annealing, suggesting improved crystalline orientation at higher temperatures. Field emission scanning electron microscopy (FE-SEM) showed enhancements in surface morphology, with increased grain size and uniformity post-annealing. Chemical uniformity was confirmed through Secondary Ion Mass Spectrometry (SIMS), Energy-Dispersive Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS). XPS revealed the presence of CZTS phases alongside oxidized phases. Annealing effectively reduced secondary phases, such as ZnO, SnO2, CuO, and SO2, enhancing the CZTS phase. An optical analysis demonstrated that annealing at 200 °C in an air atmosphere reduced the band gap from 1.53 eV to 1.38 eV. In contrast, annealing at 400 °C and 450 °C in a sulfur atmosphere increased the band gap to 1.59 eV and 1.63 eV, respectively. The films exhibited p-type conductivity, as inferred from a valence band structure analysis. Density Functional Theory (DFT) calculations provided insights into the observed band gap variations, further substantiating the findings.
