Physics / Fizik

Permanent URI for this collectionhttps://hdl.handle.net/11147/6

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  • Article
    Citation - WoS: 6
    Citation - Scopus: 5
    Structural and Optical Characteristics of Antimony Selenosulfide Thin Films Prepared by Two-Step Method
    (Springer, 2022) Türkoğlu, Fulya; Ekren, Memduh Emirhan; Cantaş, Ayten; Yakıncı, Kübra; Gündoğan, Hazal; Aygün, Gülnur; Özyüzer, Lütfi
    Antimony triselenide (Sb2Se3) is one of the most promising absorber material choices among the inorganic semiconductors that has attracted much attention today. However, highest recorded efficiencies for Sb2Se3 solar cells are still lower than ideal. Exploring antimony selenosulfide (Sb-2(SxSe1-x)(3)) to increase device performance is one option because some features of alloyed Sb-2(SxSe1-x)(3) depend on composition such as bandgap and band position. In this study, two-step process was used to grow Sb-2(SxSe1-x)(3) thin films. In the first stage, Sb2Se3 thin films were deposited on soda lime glass substrates using direct current magnetron sputtering technique. In the second stage, Sb2Se3 thin films were exposed to sulfurization process in a quartz ampoule to obtain Sb-2(SxSe1-x)(3) thin films. Characterization results showed that morphological, optical, and structural properties of Sb-2(SxSe1-x)(3) thin films grown by presented method were highly dependent on amount of sulfur in the films. By the adjustment of the S/S + Se atomic ratio, Sb-2(SxSe1-x)(3) absorber materials with suitable bandgap, favorable orientation and compact morphology can be obtained for photovoltaic applications.
  • Book Part
    Citation - Scopus: 1
    Thz Sources and Detectors Fabricated From High Temperature Superconductors
    (Springer, 2021) Demirhan, Yasemin; Türkoğlu, Fulya; Altan, Hakan; Sabah, Cumali; Özyüzer, Lütfi
    High temperature superconductors have unique properties that can be useful in the THz region, single crystal constituted from superconducting CuO2-layers could sustain high voltages across the junctions and they are coupled through the intrinsic Josephson Effect this maintains the potential for very intense, coherent radiation which spreads over the THz gap. We investigated various experimental techniques to fabricate THz sources, bolometers and filters for efficient THz emission and detection. Rectangular mesa structures were fabricated on Bi2Sr2CaCu2O8-x (Bi2212) single crystal superconductors using standard e-beam lithography and Ar ion beam etching systems and an emitted power as high as 60 ?W at frequencies up to 0.85 THz was detected from micron sized continuous wave terahertz sources. We also fabricated bolometric microchips for THz detection purpose from Bi2212 single crystals. Bi2212 microchips detected the signals and response time were calculated, our results have clearly shown that Bi2212 single crystals are potential candidates for THz detection. The detection properties and sensitivity of bolometer chips can be further improved by integrating an antenna and filter structures. In order to investigate this we have fabricated metamaterial THz filters based on metals and YBa2Cu3Ox superconducting thin films with metal-mesh shape and a unique fourcross shape pattern. Both a THz time domain spectrometer and a Fourier transform infrared spectrometer (FTIR) were used to investigate the performance of these filters and the results were compared with simulations done with a commercially available electromagnetic simulation software. © Springer Nature B.V. 2021.