Yazar "Biel, Blanca" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim
    Öğe
    A computational study of van der Waals tunnel transistors: Fundamental aspects and design challenges
    (Institute of Electrical and Electronics Engineers Inc., 2015) Cao, Jiang; Logoteta, Demetrio; Özkaya, Özkaya; Biel, Blanca; Cresti, Alessandro; Pala, Marco; Esseni, David
    We propose a model Hamiltonian for van der Waals tunnel transistors relying on a few physical parameters that we calibrate against DFT band structure calculations. This approach allowed us to develop a fully three-dimensional (3-D) NEGF based simulator and to investigate fundamental and design aspects related to van der Waals tunnel transistors, such as: (a) area and edge tunneling components, and scaling with device area; (b) impact of top gate alignment and back-oxide thickness on the device performance; (c) influence of inelastic phonon scattering on the device operation and sub-threshold swing; (d) benchmarking of switching energy and delay. © 2015 IEEE.
  • Küçük Resim
    Öğe
    MXene-based Ti2C/Ta2C lateral heterostructure: an intrinsic room temperature ferromagnetic material with large magnetic anisotropy
    (Royal Society of Chemistry, 2023) Özcan Özkaya, Sibel; Biel, Blanca
    Two-dimensional (2D) lateral heterostructures (LH) combining Ti2C and Ta2C MXenes were investigated by means of first-principles calculations. Our structural and elastic properties calculations show that the lateral Ti2C/Ta2C heterostructure results in a 2D material that is stronger than the original isolated MXenes and other 2D monolayers such as germanene or MoS2. The analysis of the evolution of the charge distribution with the size of the LH shows that, for small systems, it tends to distribute homogeneously between the two monolayers, whereas for larger systems electrons tend to accumulate in a region of ?6 Å around the interface. The work function of the heterostructure, one crucial parameter in the design of electronic nanodevices, is found to be lower than that of some conventional 2D LH. Remarkably, all the heterostructures studied show a very high Curie temperature (between 696 K and 1082 K), high magnetic moments and high magnetic anisotropy energies. These features make (Ti2C)/(Ta2C) lateral heterostructures very suitable candidates for spintronic, photocatalysis, and data storage applications based upon 2D magnetic materials.
  • Küçük Resim
    Öğe
    Operation and design of van der waals tunnel transistors: a 3-d quantum transport study
    (IEEE, 2016) Cao, Jiang; Logoteta, Demetrio; Özkaya, Sibel; Biel, Blanca; Cresti, Alessandro; Pala, Marco; Esseni, David
    We propose a model Hamiltonian for van der Waals tunnel transistors (vdW-TFETs) relying on few physical parameters calibrated against density functional theory (DFT) band structure calculations. Based on this model, we develop a fully 3-D nonequilibrium Green's function simulator including electron-phonon scattering, and we investigate some fundamental aspects and design challenges related to vdW-TFETs based on single-layer MoS2 and WTe2. In particular, we devote a specific analysis to the impact of top gate alignment and back-oxide thickness on the device performance. Our results suggest that the vdW-TFETs can provide very small values of subthreshold swing (SS) and fairly good ON-state current. However, these devices also pose specific design challenges related to the geometrical features of gated regions, and their ultimate SS may be lower limited by inelastic phonon scattering.
  • [ X ]
    Öğe
    Point-like vacancies in two-dimensional transition metal dichalcogenides
    (Institute of Physics, 2024) Özcan, Sibel; Gallardo, Aurelio; Biel, Blanca
    his study explores the realm of two-dimensional transition metal dichalcogenides (TMDs), examining some of the most prevalent defects. Employing density functional theory, we scrutinize three common defect types across four extensively studied TMDs: MoS2, MoSe2, WS2, and WSe2. Our investigation spans the energetics of these defects, unveiling the most stable ones, and unraveling the alterations in structural and electronic properties induced by their presence. As a further step towards practical applications, we simulate the images that would be captured by both Atomic and Kelvin Probe Force Microscopes, aiming at a facile identification of these defects when probed at the microscopic level.