Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 12: HL Poster I
HL 12.32: Poster
Montag, 1. April 2019, 17:30–20:00, Poster E
Boosting the Sensitivity and Selectivity of a Nanotube-Based NO2 Gas Sensor: A First-Principles Investigation — Seyed Shahim Vedaei1, •Ebrahim Nadimi1,2, and Michael Schreiber2 — 1Faculty of Electrical Engineering, Center for Computational Micro and Nanoelectronics, K. N. Toosi University of Technology, Tehran, Iran. — 2Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz, Germany.
The sensing properties of carbon-nanotube (CNT) boron-nitride-nanotube (BNNT) heterostructures toward NO2, O2 and H2O have been theoretically investigated applying first-principles density-function theory in combination with non-equilibrium Green’s function formalism. The core idea is to change the current-flow mechanism in CNT to a quantum-mechanical tunneling process by introducing BNNT insulating layers within the CNT. Due to the strong sensitivity of the tunneling current to the barrier height and the influence of adsorbed agent on the position of the band edges in the BNNT layer a very high level of sensitivity is expected for the proposed device. The binding energies and current as well as the device sensitivity have been calculated for energetically favorable adsorption geometries of NO2, O2 and H2O molecules. In general NO2 and O2 show higher sensitivity compared to H2O molecule. In order to increase the selectivity, the application of a vertical electric field on the BNNT part of the device is suggested. It is shown that by collecting the signals at different vertical electric fields a very good selectivity can be expected toward NO2, O2 and H2O gases.