Physics / Fizik
Permanent URI for this collectionhttps://hdl.handle.net/11147/6
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Article Study of the Effect of Various Chemical Polishing Treatments on Mbe-Grown Cdte/Gaas (211)b Heterostructures(Sakarya University, 2020) Bilgilisoy, E.; Özçeri, E.; Tarhan, E.A three-inch-diameter high quality CdTe thin film was grown on a GaAs (211)B substrate by molecular beam epitaxy (MBE) in ultra-high vacuum conditions. The CdTe/GaAs (211)B heterostructure was then cut into several sample pieces. A few as-grown sample pieces were subjected to chemical etching solutions which created etch pits on the surface. The scanning electron microscopy images of such samples were used to calculate the etch pit densities on the surface. In addition, several as-grown samples were subjected to chemical polishing treatments under different conditions to quantify the removal of O and Te-O structures from the surface. Atomic force microscopy was used to determine as-grown and polished surface morphology and the polish rate of chemical solutions. A study of the surface stoichiometry and the chemical composition of the as-grown and polished CdTe (211)B surfaces were carried out by using X-ray photoelectron spectroscopy. Bulk structural qualities of the as-grown and polished samples were studied in terms of the vibrational and phonon modes via confocal Raman spectroscopy. From a comparative analyses of the results, the best chemical polishing conditions for the MBE-grown CdTe (211)B heterostructure were determined. © 2020, Sakarya University. All rights reserved.Article Investigation of Interactions of Acetylene Molecules With an Iron Nanowire and Its Effects on Mechanical Tensile Properties(Sakarya University, 2021) Aral, G.Understanding complex atomistic-scales interactions mechanisms of reactive acetylene (C2H2) molecules with reactive pure iron nanowires (Fe NWs) including its effects on the tensile mechanical properties of NWs is a crucial task in nanotechnology, especially having practical significance in the mechanical reliability, durability and stability. Therefore, we performed molecular dynamics (MD) simulations based on ReaxFF reactive force field interatomic potential model to investigate the interactions of C2H2 molecules with surface of cylindrical pure Fe NW and its fundamental effects on the tensile mechanical deformations properties of NWs at three different strain rates. Our results reveal that the chemical energetic reactions on the free surface of cylindrical Fe NW with C2H2 molecules in the gas phase form FexCyHz shell layer at temperature T=300 K. The presence of FexCyHz shell layer on the free surface of NW has a significant effect on the mechanical tensile deformation mechanism of the NWs. © 2021, Sakarya University. All rights reserved.Article Citation - WoS: 32Citation - Scopus: 28Search for a Heavy Gauge Boson W′ in the Final State With an Electron and Large Missing Transverse Energy in Pp Collisions at S=7 Tev(Elsevier B.V., 2011) Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Lustermann, W.A search for a heavy gauge boson W′ has been conducted by the CMS experiment at the LHC in the decay channel with an electron and large transverse energy imbalance ET miss, using proton–proton collision data corresponding to an integrated luminosity of 36 pb−1. No excess above standard model expectations is seen in the transverse mass distribution of the electron-ET miss system. Assuming standard-model-like couplings and decay branching fractions, a W′ boson with a mass less than 1.36 TeV/c2 is excluded at 95% confidence level. © 2011 CERNArticle Citation - WoS: 183Citation - Scopus: 200Search for Supersymmetry in Pp Collisions at 7 Tev in Events With Jets and Missing Transverse Energy(Elsevier B.V., 2011) Khachatryan, V.; Demir, Durmuş Ali; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Marchica, C.A search for supersymmetry with R-parity conservation in proton–proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 pb −1 collected by the CMS experiment at the LHC. The search is performed in events with jets and significant missing transverse energy, characteristic of the decays of heavy, pair-produced squarks and gluinos. The primary background, from standard model multijet production, is reduced by several orders of magnitude to a negligible level by the application of a set of robust kinematic requirements. With this selection, the data are consistent with the standard model backgrounds, namely tt¯, W + jet and Z + jet production, which are estimated from data control samples. Limits are set on the parameters of the constrained minimal supersymmetric extension of the standard model. These limits extend those set previously by experiments at the Tevatron and LEP colliders. © 2011 CMS CollaborationArticle Citation - WoS: 16Citation - Scopus: 17Superconducting Gap and Pseudogap From Tunneling Conductance on Bi2sr2cacu2og+δ With Various Oxygen Concentration(Elsevier, 2000) Miyakawa, N.; Zasadzinski, J.F.; Ozyuzer, L.; Guptasarma, P.; Kendziora, C.; Hinks, D.G.; Gray, K.E.The evolution of tunneling spectra on Bi2Sr2CaCu2Og+δ measured by SIN point contacts, SIS break junctions and STM/STS has been studied as a function of doping and temperature. The detailed examinations of the spectra show that the energy gap measured at low temperature appear to be due to superconducting pairing. The doping dependence of the superconducting gap at low temperature suggests a strong connection to the pseudogap temperature, T*, and this indicates that the pseudogap region is at least partly a consequence of some form of precursor superconductivity. In addition, dip/hump structures observed at high bias scale approximately with not only Δ but also superexchange interaction J over the entire doping range examined, indicating these features are linked to the underlying interaction responsible for superconductivity. We suggest that the hump structure may originate from short-range magnetic correlations. © 2000 Elsevier Science B.V All rights reserved.