Enhancement of CZTS photovoltaic device performance with silicon at back-contact: A study using SCAPS-1D

• Published in: Solar energy 2022-04, Vol.236, p.301-307
• Main Authors: Kumari, Neha, Ingole, Sarang
• Format: Article
• Language: English
• Subjects: Capacitance; Circuits; CZTS; Heterojunction; Molybdenum; Open circuit voltage; Photovoltaic cells; Photovoltaics; Quantum efficiency; SCAPS-1D; Selenium; Short circuit currents; Short-circuit current; Silicon; Solar cells; Solar energy
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2022.03.005

•CZTS PV devices were studied using SCAPS-1D with p+ type Si at back-contact.•a-Si:H eliminates downward band-bending at the back-contact thus improving Jsc.•The η values are 16.83% and 21.85% with c-Si and a-Si:H, respectively.•η is further enhanced when CZTS is replaced by CZTSSe while Si being at the back-contact. Cu2ZnSnS4 (CZTS) is a promising photo-absorber material for photovoltaics (PV) applications. Molybdenum which is employed as a back-contact metal in the CZTS based PV devices, is not the best choice. In the present work, we have used one-dimensional Solar Cell Capacitance Simulator (SCAPS-1D) to study the effect of replacing molybdenum with p+-type silicon (Si), both in the crystalline and hydrogenated amorphous phases. The device models with these two phases of Si at the back-contact led to photoconversion efficiencies (η) of 16.83 and 21.85%, respectively. Moreover, with Si at the back-contact, the performance can be further enhanced to 22.45% with the introduction of selenium in the chalcogenide sub-lattice. These improved η values are due to improved short-circuit current and fill-factors; the open-circuit voltage remains unchanged. The reduction of Schottky barrier at the back-contact with the use of Si is resulting in these beneficial effects.