Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Sb2se3 Absorber Layered Solar Cell Fabrication and Characterization(01. Izmir Institute of Technology, 2021) Kurtuldu, Seher Hazal; Aygün, Gülnur; Tarhan, Enver; Tarhan, Enver; Aygün Özyüzer, Gülnur; Tarhan, Enver; 01. Izmir Institute of Technology; 04.05. Department of Pyhsics; 04. Faculty of ScienceThin-film antimony selenide (Sb2Se3) solar cells have gained attention as a high-potential photovoltaic technology around the world. Outstanding features like a high absorption coefficient, a suitable direct bandgap, and good hole mobility make Sb2Se3 a promising absorber material for solar cell applications. It has demonstrated a very rapid growth reaching 9.2% power conversion efficiency (PCE) in only 7 years after intensive studies. In the present thesis, first of all Sb2Se3 thin films were deposited on soda lime glasses (SLGs) and investigated using energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), scanning electron microscopy (SEM), spectrophotometry and Raman spectroscopy. Structural and optical studies were carried out depending on the thickness, used argon (Ar) gas flow rate and post-annealing temperature of the Sb2Se3 films in order to optimize the absorber layer to be used in solar cell. This study revealed that key parameters such as band gap energy and crystal structure of the Sb2Se3 thin films affected by the thickness, Ar gas flow rate during deposition and post-annealing temperature. In addition, oxide phase formation was also found to be related to these growth parameters. Finally, SLG/ITO/Zn(O,S)/Sb2Se3/Ag for superstrate configuration and both SLG/Mo/Sb2Se3/CdS/ITO and SLG/Mo/Sb2Se3/CdS/ZnS/ITO devices fabricated for substrate configuration solar cells. Since Zn(O,S)/Sb2Se3 heterojunction has not been studied before in the literature, this study will be the first. At the end of the electrical analysis, the best conversion efficiency of 3.9% was achieved by the solar cell with the substrate configuration.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 TechnologyThis 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.