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: 6Citation - Scopus: 6Weak Dependence of Voltage Amplification in a Semiconductor Channel on Strain State and Thickness of a Multidomain Ferroelectric in a Bilayer Gate(American Chemical Society, 2023) Misirlioglu, I.B.; Yapici, M.K.; Sendur, K.; Okatan, M.B.Ferroelectric/dielectric layered stacks are of special interest as gate oxides in the pursuit of designing low-power transistors, where the electrostatics of such stacks are thought to provide a means to allow for voltage amplification in the semiconductor channel. Strain and thickness dependence of the response of such a gate stack in relation to voltage amplification in a semiconductor channel becomes important to identify, which is what we study in this work using a thermodynamic approach. For a ferroelectric multidomain state as the stable phase in the stack, our findings show that a limited magnitude of voltage amplification appears to be feasible. Voltage amplification at the semiconductor surface is computed to hardly exceed 1.2 in thick bilayers (40 nm) for strains stabilizing the multidomain state and attains even less than this value for the thinner stacks. © 2023 American Chemical Society.Article Citation - WoS: 105Citation - Scopus: 105Pentagonal Monolayer Crystals of Carbon, Boron Nitride, and Silver Azide(American Institute of Physics, 2015) Yağmurcukardeş, Mehmet; Şahin, Hasan; Kang, J.; Torun, E.; Peeters, François M.; Senger, Ramazan TuğrulIn this study, we present a theoretical investigation of structural, electronic, and mechanical properties of pentagonal monolayers of carbon (p-graphene), boron nitride (p-B2N4 and p-B4N2), and silver azide (p-AgN3) by performing state-of-the-art first principles calculations. Our total energy calculations suggest feasible formation of monolayer crystal structures composed entirely of pentagons. In addition, electronic band dispersion calculations indicate that while p-graphene and p-AgN3 are semiconductors with indirect bandgaps, p-BN structures display metallic behavior. We also investigate the mechanical properties (in-plane stiffness and the Poisson's ratio) of four different pentagonal structures under uniaxial strain. p-graphene is found to have the highest stiffness value and the corresponding Poisson's ratio is found to be negative. Similarly, p-B2N4 and p-B4N2 have negative Poisson's ratio values. On the other hand, the p-AgN3 has a large and positive Poisson's ratio. In dynamical stability tests based on calculated phonon spectra of these pentagonal monolayers, we find that only p-graphene and p-B2N4 are stable, but p-AgN3 and p-B4N2 are vulnerable against vibrational excitations.