Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Publisher: search.filters.publisher.Izmir Institute of TechnologySubject: search.filters.subject.CZTS

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  • Master Thesis
    Efficiency Studies of Cu2znsns2 Thin Film Solar Cell
    (Izmir Institute of Technology, 2018) Meriç, Ece; Aral, Gürcan; Özyüzer, Lütfi; Özyüzer, Lütfi; Aral, Gürcan; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    Cu2ZnSnS4 (CZTS) is a promising candidate as an absorber layer for thin film solar cells due to not only its low cost but also nontoxic properties contrary to alternative materials such as CdTe and Cu(In,Ge)Se2 (CIGS). Recently, CZTS and similar chalcogenides have attracted remarkable attention because of their suitable properties. In my thesis; I studied the efficiency of Cu2ZnSnS4 thin film solar cells for various stoichiometric cases. Besides, the effect of back contact, buffer layer thickness and sulfurization time were investigated. CZTS thin films were fabricated by DC magnetron sputtering method on Molybdenum (Mo) coated Soda Lime Glass (SLG) and Ti foil substrates. Cu, Sn, Zn, Cu layers were, respectively, deposited on the substrates, and then sulfurization process was followed as the second step in the growth process to obtain a desirable CZTS formation. The as grown CZTS structure was investigated using Raman and X-Ray Diffraction (XRD) spectroscopies. Scanning electron microscopy (SEM) was used to investigate the surface morphology of the films. Energy dispersive spectroscopy (EDS) was used to define the chemical structure of the surface of the films. Next, a CdS buffer layer was deposited on CZTS absorber layer using CBD method at 85oC for varying times (60, 75 and 90 min). Then, ZnO and Al doped ZnO (AZO) layers were deposited on CdS. J-V curves were obtained for SLG/Mo/CZTS/CdS/ZnO/AZO solar cell structure. The photovoltaic characteristic of solar cells was studied and their dependence on CdS deposition time were found. Among all the device we produced, the highest efficiency was obtained for the device with the lowest CdS deposition time. In addition; effect of sulfurization time on the solar cell conversion efficiency was studied.
  • Master Thesis
    Investigation of Sulfurization Temperature Effects on Cu2znsns4 Thin Flims Prepared by Magnetron Sputtering Method on Flexible Titanium Foil Substrates for Thin Flim Solar Cells
    (Izmir Institute of Technology, 2017) Buldu, Dilara Gökçen; Aygün, Gülnur; Aygün Özyüzer, Gülnur; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    This thesis presents the effect of sulfurization temperature on Cu2ZnSnS4 (CZTS) thin films on flexible titanium (Ti) foil substrates. The CZTS films was produced by using a two-stage method. In the first step, the metallic precursor layers Cu/Sn/Zn/Substrate were deposited on Ti foil substrate by using DC magnetron sputtering method. In the second step, the deposited metal precursors were sulfurized in a graphite box under Argon (Ar) ambient inside a tubular furnace under a definite temperature. To understand the effects of temperature on the formation of the CZTS structure several analyses were performed. Our samples, each with a different sulfurization temperature; ranging from 530 to 580 oC, were carried out and the structural properties of the absorber layer was determined. XRD measurements showed a sharp and intense peak coming from the (112) planes which was a strong evidence for good crystallinity. The intensity of (112) plane became a sharp and intense with increasing sulfurization temperature. Raman spectroscopy of the sulfurized thin films revealed that, the kesterite structure CZTS thin film were obtained with increasing sulfurization temperature. Electron Dispersive Spectroscopy (EDS) was also used for the compositional analysis of the thin films. EDS analysis showed that the films were grown with a Cu-poor Zn-rich composition. From these analyses we conclude that no interface formation occurred between the substrate and the CZTS thin films, hence, a buffer layer was not required. It was also seen that Ti foil was suitable as substrate for the growth of CZTS thin films with desired properties. We also conclude that the sulfurization temperature plays a crucial role for producing good quality CZTS thin films on Ti foil substrate.