Photonics / Fotonik

Permanent URI for this collectionhttps://hdl.handle.net/11147/2590

Browse

Filters

20172

Settings

Institution Author: search.filters.institutionAuthor.Bacaksız, CihanPublisher: search.filters.publisher.American Physical Society

Search Results

Now showing 1 - 2 of 2
  • Article
    Citation - WoS: 14
    Citation - Scopus: 14
    Hydrogen-Induced Sp2-Sp3 Rehybridization in Epitaxial Silicene
    (American Physical Society, 2017) Solonenko, Dmytro; Dzhagan, Volodymyr; Şahin, Hasan; Bacaksız, Cihan; Şahin, Hasan; Zahn, Dietrich R. T.; Vogt, Patrick; 04.04. Department of Photonics; 04. Faculty of Science; 01. Izmir Institute of Technology
    We report on the hydrogenation of (3×3)/(4×4) silicene epitaxially grown on Ag(111) studied by in situ Raman spectroscopy and state-of-the-art ab initio calculations. Our results demonstrate that hydrogenation of (3×3)/(4×4) silicene leads to the formation of two different atomic structures which exhibit distinct spectral vibrational modes. Raman selection rules clearly show that the Si atoms undergo a rehybridization in both cases from a mixed sp2-sp3 to a dominating sp3 state increasing the distance between the two silicene sublattices. This results in a softening of the in-plane and a stiffening of the out-of-plane phonon modes. Nevertheless, hydrogenated epitaxial silicene retains a two-dimensional nature and hence can be considered as epitaxial silicane. The level of hydrogenation can be determined by the intensity ratio of the Raman modes with different symmetries.
  • Article
    Citation - WoS: 23
    Citation - Scopus: 25
    H-Aln Van Der Waals Bilayer Heterostructure: Tuning the Excitonic Characteristics
    (American Physical Society, 2017) Bacaksız, Cihan; Dominguez, A.; Şahin, Hasan; Senger, Ramazan Tuğrul; Senger, Ramazan Tuğrul; 04.04. Department of Photonics; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    Motivated by recent studies that reported the successful synthesis of monolayer Mg(OH)2 [Suslu, Sci. Rep. 6, 20525 (2016)2045-232210.1038/srep20525] and hexagonal (h-)AlN [Tsipas, Appl. Phys. Lett. 103, 251605 (2013)APPLAB0003-695110.1063/1.4851239], we investigate structural, electronic, and optical properties of vertically stacked h-AlN and Mg(OH)2, through ab initio density-functional theory (DFT), many-body quasiparticle calculations within the GW approximation and the Bethe-Salpeter equation (BSE). It is obtained that the bilayer heterostructure prefers the AB′ stacking having direct band gap at the Γ with Type-II band alignment in which the valance band maximum and conduction band minimum originate from different layer. Regarding the optical properties, the imaginary part of the dielectric function of the individual layers and heterobilayer are investigated. The heterobilayer possesses excitonic peaks, which appear only after the construction of the heterobilayer. The lowest three exciton peaks are analyzed in detail by means of band decomposed charge density and the oscillator strength. Furthermore, the wave function calculation shows that the first peak of the heterobilayer originates from spatially indirect exciton where the electron and hole localized at h-AlN and Mg(OH)2, respectively, which is important for the light harvesting applications.