Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 2Scalable Growth of Optically Uniform Mows2 Alloys by Sulfurization of Ultrathin Mo/W Stacks(Elsevier Sci Ltd, 2025) Panasci, Salvatore Ethan; Schiliro, Emanuela; Koos, Antal; Kutlu, Tayfun; Sahin, Hasan; Roccaforte, Fabrizio; Giannazzo, FilippoTwo-dimensional (2D) transition metal dichalcogenides (TMDs) ternary alloys, such as MoxW1-xS2, are very appealing for the possibility of continuously tuning their excitonic bandgap by the composition. However, the deposition of ultra-thin (monolayers or few-layers) alloys with laterally uniform composition on large area represents a main challenge of currently adopted synthesis methods. In this work, we demonstrated the growth of highly uniform Mo0.5W0.5S2 bi-layers on cm2 size SiO2/Si substrates by employing a simple and scalable approach, i.e. the sulfurization of a pre-deposited ultra-thin Mo/W stack at a temperature of 700 degrees C. Comparison of Mo(1.2 nm)/SiO2, W(1.2 nm)/SiO2, and Mo(1.2 nm)/W(1.2 nm)/SiO2 samples after identical sulfurization conditions revealed very different results, i.e. (i) a uniform monolayer (1L) MoS2 film, (ii) separated multilayer WS2 islands, and (iii) a uniform bilayer (2L) Mo0.5W0.5S2 film. This indicates how W surface diffusion and coalescence on SiO2 surface plays a main role in WS2 islands formation, whereas the reaction between S vapour with Mo films or Mo/W stacks represents the dominant mechanism for the formation of MoS2 and the MoWS2 alloy. Micro-photoluminescence (PL) mapping of the obtained 2L-Mo0.5W0.5S2 film showed an excellent uniformity of light emission on large area with an exciton peak at 1.97 eV, significantly blue-shifted with respect to PL emission of 1L-MoS2 at 1.86 eV. Such highly uniform optical properties make the grown MoWS2 alloy very promising for optoelectronic applications.Article Citation - WoS: 5Citation - Scopus: 5Effect of the Synthesis Conditions on the Properties of Co Embedded Porous Si Nanostructures(Elsevier Ltd., 2019) Çetinel, Alper; Artunç, Nurcan; Tarhan, EnverThe electrodeposition of cobalt in the porous silicon (PSi) substrate was investigated in terms of the deposition times and current densities. The PSi/Co samples were characterized by SEM, XRD, Raman, and photoluminescence (PL) spectroscopies. The results indicated that for all current densities, the PL intensities of PSi/Co samples with shorter deposition times (t(s) <= 20 min) increased due to spherical Co nanoparticles (NPs) could be created the new recombination centers, compared to that of the undeposited PSi. On the other hand, the PL intensity of PSi/Co samples significantly decreased at longer deposition times (t(1) > 20 min) because of larger Co NP cluster promoted the formation of non-radiative centers. The increased PL intensities in samples with t(s) were attributed to both the quantum confinement effect and surface effects. PL analyses also suggested that after exposure to air for 60 days, PL characteristics of PSi/Co were stabilized depending on deposition time and current density.Article Citation - WoS: 16Citation - Scopus: 18Study of Undoped and Indium Doped Zno Thin Films Deposited by Sol Gel Method(Springer Verlag, 2018) Medjaldi, M.; Touil, O.; Boudine, B.; Zaabat, M.; Halimi, O.; Sebais, M.; Özyüzer, LütfiIn this paper, we report the effects of Indium doping concentrations (from 0 to 10wt%) on the structural, morphological, and optical properties of deposited In doped ZnO (IZO) thin films prepared by the sol–gel method through the dip coating technique. X-ray diffraction (XRD) analysis indicates that all ZnO thin films have a polycrystalline nature with a hexagonal wurtzite phase with (002) as a preferential orientation. XRD results demonstrate that the particle size of ZnO decreased with the increase in Indium concentrations. Raman scattering spectra confirmed the wurtzite phase and the presence of intrinsic defects in our samples. Energy dispersive spectroscopy (EDS) and the X-ray photoelectron spectroscopy (XPS) measurements, confirmed the presence of zinc, oxygen and indium elements which is in agreement with XPS results. The photoluminescence (PL) spectra of the films exhibit defects-related visible emission peaks, with intensities differing owing to different concentrations of zinc vacancies. UV–Vis spectrometer measurements show that all the films are highly transparent in the visible wavelength region (≥ 70%) and presented two different absorption edges at about 3.21 eV and 3.7 eV, these may be correspond to the band gap of zinc oxide and indium oxide respectively.Article Citation - WoS: 39Citation - Scopus: 39Polarized Emission From Cspbbr3 Nanowire Embedded-Electrospun Pu Fibers(IOP Publishing Ltd., 2018) Güner, Tuğrul; Topçu, Gökhan; Savacı, Umut; Genç, Aziz; Sarı, Emre; Demir, Mustafa MuammerInterest in all-inorganic halide perovskites has been increasing dramatically due to their high quantum yield, band gap tunability, and ease of fabrication in compositional and geometric diversity. In this study, we synthesized several hundreds of nanometer long and ∼4 nm thick CsPbBr3 nanowires (NWs). They were then integrated into electrospun polyurethane (PU) fibers to examine the polarization behavior of the composite fiber assembly. Aligned electrospun fibers containing CsPbBr3 NWs showed a remarkable increase in the degree of polarization from 0.17-0.30. This combination of NWs and PU fibers provides a promising composite material for various applications such as optoelectronic devices and solar cells.