Conference Paper

Permanent URI for this collectionhttps://hdl.handle.net/10361/6942

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Transition in electronic transport properties of graphene nanoribbon due to the adsorption of atoms and molecules
(© 2015 Institute of Electrical and Electronics Engineers Inc., 2015) Shakil, Shifur Rahman; Saha, Atanu Kumar; Bhuian, Md. Belal Hossain; Department of Electrical and Electronic Engineering
The adsorption effects of gas molecules on semiconducting armchair graphene nanoribbon (A-GNR) are studied considering on the significant changes over current-voltage characteristics, device density of states and electrostatic difference potential. The orientation of gas molecules and adsorption sites play an important role on charge transfer between the graphene surface and the molecules. The charge transfer mechanism is discussed in the light of molecular orbital theory. We have used three gas molecules-CO2, NH3 and NO as adsorbates and chose such orientation that adsorbates can act only as donor. Finally, we have made a conclusion that semiconducting A-GNR shows metallic behaviour after adsorbing optimum number of adsorbates corresponding to the area of A-GNR. Such semiconducting to metal transition can be used as sensing parameters.
Vapor adsorption limitation of graphene nanoribbons in quasi conductance increment: a NEGF approach
(© 2015 Institute of Electrical and Electronics Engineers Inc., 2015) Shakil, Shifur Rahman; Zohra, Fatema Tuz; Pramanik, Parna; Tushar, Raihanul Islam; Saha, Atanu Kumar; Bhuian, Md Belal Hossain; Department of Electrical and Electronic Engineering
The adsorption of H2O molecules on Armchair Graphene Nanoribbons (A-GNR) was theoretically studied using Non Equilibrium Green Function (NEGF) formalism to determine Device Density of States (DDOS), Electrostatic Effective Potential (EDP), Conductivity (G) and Current-Voltage (I-V) characteristics. This paper analyzed the performance of semiconducting graphene nanoribbon (N=10), metallic graphene nanoribbon (N=11) and cascade hetero-graphene nanoribbon to consider the effect of H2O adsorption on GNR and conclude that for low voltage application semiconducting A-GNR will be a better choice over metallic A-GNR and cascade A-GNR. The optimum area for adsorbing maximum number of H2O molecules on A-GNR has been studied. It has been observed that the increment of quasi conductance resulting sensing performance for limited number of H2O adsorption. To overcome this problem, a new device model has been proposed.
Numerical study on graphene nanoribbon quantum well-in-well interband and intersubband photodetector
(© 2015 Institute of Electrical and Electronics Engineers Inc., 2015) Saha, Atanukumar; Saha, Gobinda; Rashid, A.B. M Harun Ur; Department of Electrical and Electronic Engineering
The optical properties of well in well structure formed by armchair graphene nanoribbons (A-GNRs) are studied. A-GNR sheet is modeled by 3rd nearest tight-binding parameter. The optical properties are studied by employing the self-consistent simulation between Non-equilibrium Green's function method and electrostatic Hartree potential distribution. The proposed device structure can incorporate both of the interband and intersubband transitions depending on a back gate voltage. The optical absorption frequency can be varied through the back gate voltage. The confined energy states and quantum efficiency of the device have been determined along with the dark current dependence on the bias voltages.
Double quantum well resonant tunneling negative differential resistance device design using graphene nanoribbons
(© 2015 Institute of Electrical and Electronics Engineers Inc., 2015) Saha, Gobinda; Saha, Atanukumar; Harun-Ur Rashid, A.B.M.; Department of Electrical and Electronic Engineering
In this paper double quantum well resonant tunneling negative differential resistance (NDR) device based on intrinsic armchair graphene nanoribbon (A-GNR) is proposed. Non-equilibrium Green's function (NEGF) based transport equation was coupled with Poisson's equation to obtain the desired device characteristics. This device shows promising results including the NDR effect at very low bias, at 0.12V, with peak current of 1.78μA and peak to valley current ratio (PVCR) of ∼20. We further show that the device performance has strong dependence on back gate voltage.

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