Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Access Right: Open AccessAuthor: search.filters.author.Kang, Jun

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  • Article
    Citation - WoS: 8
    Citation - Scopus: 8
    Strain Tunable Band Structure of a New 2d Carbon Allotrope C-568
    (IOS Press, 2020) Gao, Qiang; Kang, Jun; Şahin, Hasan
    Recently, C(568)has emerged as a new carbon allotrope, which shows semiconducting properties with a band gap around 1 eV and has attracted much attention. In this work, the external strain effects on the electronic properties of C(568)have been studied theoretically through first-principle calculations. The numerical results show that while in-plane uniaxial and biaxial strains both reduces the band gap of C(568)in case of tensile strain, their effects are quite different in the case of compressive strain. With increasing compressive uniaxial strain, the band gap of C(568)first increases, and then dramatically decreases. In contrast, the application of compressive biaxial strain up to -10% only leads to a slight increase of band gap. Moreover, an indirect-to-direct gap transition can be realized under both types of compressive strain. The results also show that the optical anisotropy of C(568)can be induced under uniaxial strain, while biaxial strain does not cause such an effect. These results indicate good strain tunability of the band structure of C-568, which could be helpful for the design and optimization of C-568-based nanodevices.
  • Article
    Citation - WoS: 14
    Citation - Scopus: 12
    Octahedrally Coordinated Single Layered Caf2: Robust Insulating Behaviour
    (Royal Society of Chemistry, 2020) Başkurt, Mehmet; Kang, Jun; Şahin, Hasan
    Using first-principles calculations, the structural, vibrational, and electronic properties of single-layered calcium fluoride (CaF2) are investigated. The dynamical stability of 1T-CaF2 is confirmed by the phonon dispersions. Raman active vibrational modes of 1T-CaF2 enable its characterization via Raman spectroscopy. In addition, the calculated electronic properties of 1T-CaF2 confirmed insulating behavior with an indirect wide band gap which is larger than that of a well-known single-layered insulator, h-BN. Moreover, one-dimensional nanoribbons of CaF2 are investigated for two main edge orientations, namely zigzag and armchair, and it is revealed that both structures maintain the 1T nature of CaF2 without any structural edge reconstructions. Electronically, both types of CaF2 nanoribbons display robust insulating behavior with respect to the nanoribbon width. The results show that both the 2D and 1D forms of 1T-CaF2 show potential in nanoelectronics as an alternative to the widely-used insulator h-BN with its similar properties and wider electronic band gap.
  • Article
    Citation - WoS: 67
    Citation - Scopus: 66
    Tis3 Nanoribbons: Width-Independent Band Gap and Strain-Tunable Electronic Properties
    (American Physical Society, 2015) Kang, Jun; Şahin, Hasan; Özaydın, H. Duygu; Senger, Ramazan Tuğrul; Peeters, François M.
    The electronic properties, carrier mobility, and strain response of TiS3 nanoribbons (TiS3 NRs) are investigated by first-principles calculations. We found that the electronic properties of TiS3 NRs strongly depend on the edge type (a or b). All a-TiS3 NRs are metallic with a magnetic ground state, while b-TiS3 NRs are direct band gap semiconductors. Interestingly, the size of the band gap and the band edge position are almost independent of the ribbon width. This feature promises a constant band gap in a b-TiS3 NR with rough edges, where the ribbon width differs in different regions. The maximum carrier mobility of b-TiS3 NRs is calculated by using the deformation potential theory combined with the effective mass approximation and is found to be of the order 103cm2V-1s-1. The hole mobility of the b-TiS3 NRs is one order of magnitude lower, but it is enhanced compared to the monolayer case due to the reduction in hole effective mass. The band gap and the band edge position of b-TiS3 NRs are quite sensitive to applied strain. In addition we investigate the termination of ribbon edges by hydrogen atoms. Upon edge passivation, the metallic and magnetic features of a-TiS3 NRs remain unchanged, while the band gap of b-TiS3 NRs is increased significantly. The robust metallic and ferromagnetic nature of a-TiS3 NRs is an essential feature for spintronic device applications. The direct, width-independent, and strain-tunable band gap, as well as the high carrier mobility, of b-TiS3 NRs is of potential importance in many fields of nanoelectronics, such as field-effect devices, optoelectronic applications, and strain sensors.