SCHOTTKY TYPE HETEROJUNCTIONS IN LOW-DIMENSIONAL STRUCTURES
Abstract
A comprehensive theoretical/computational exploration of low-dimensional systems of key interest for electronics is proposed. Two kinds emerged in our recent work, supported in part by the ONR, distinctly different yet having common definitive feature of low dimensionality: 1D pure carbon chains (carbynes) and 2D truly planar interfaces, with graphene as one key component. Carbyne can be viewed, as ultimately narrow graphene nanoribbon, a chain of carbon =C=C=C=C… (observed as bridging across the graphene-graphene space-gap, or on its surface terminated at the ends by metal atoms). Our computations of electronic structure suggest a range of remarkable mechanical (in bending, tension, and torsion) and electronic properties. A metal-insulator transition is predicted, with the tantalizing possibilities for experimenting and applications. We will explore a number of accompanying phenomena: effective mass and mobility modulated by tension; changes in the scattering due to variability of the deformation potential; role of the transverse off-line modes of vibrations and how do they affect the mobility, important interactions with substrates, especially graphene. We are already in contact with experimentalists at IPCMS-Strasbourg, and at NIMS-Tsukuba, and we plan to benefit from extending such interactions. Another line of research is to obtain a fresh look onto physics of Schottky contacts in 2D or other low-D contacts, which all depart qualitatively from the workhorse models used for decades for standard 3D|3D contacts. Based on our laboratory unique expertise in structural aspects of low-D interfaces, we will now explore the specific departures in their electronic models from the canonical 3D cases. The lack of “double-layer planar capacitor” in any junction of lower than 3D dimensionality, makes conventional Schottky-Mott local charge depletion model inapplicable and calls for new approach for 2D|2D interfaces or even for a set of models (keeping in mind the “non-diagonal” 3D|2D junctions and thus up to 3! = 6 possibilities total). That is exactly the direction we intend to explore, the qualitatively novel organization of charge at the low-dimensional interfaces, and how does it affect their physical behavior in device setting. We look for developing new intuitive models which would replace or augment the way of thinking we inherit from classic 3D-material contacts. General understanding of the situation will lead to realistic accurate description, including atomistic first-principles computations, of broad variety of 2D-junctions, including important examples of Gr/BN, Gr/MX2, BN/MX2, etc. Complementary ab initio computations results will be used to create an intuitive picture of the Schottky contacts in 2D devices.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512372
Entities
People
- Boris I Yakobson
Organizations
- Office of Naval Research
- Rice University
- United States Navy