Physical insights on graphene nanoribbon mobility through atomistic simulation (original) (raw)
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Atomistic Investigation of Low-Field Mobility in Graphene Nanoribbons
IEEE Transaction on Electron Devices, 2011
We have investigated the main scattering mechanisms affecting the mobility in graphene nanoribbons using detailed atomistic simulations. We have considered carrier scattering due to acoustic and optical phonons, edge roughness, single defects, and ionized impurities, and we have defined a methodology based on simulations of statistically meaningful ensembles of nanoribbon segments. Edge disorder heavily affects the mobility at room temperature in narrower nanoribbons, whereas charged impurities and phonons are hardly the limiting factors. Results are favorably compared with the few experiments available in the literature.
Journal of Applied Physics, 2012
This paper present a study of carrier transport in graphene nanoribbon (GNR) transistors using three-dimensional quantum mechanical simulations based on a real-space approach of the non-equilibrium Green's function (NEGF) formalism in the ballistic and dissipative limit. The carrier transport parameters are determined in the presence of electron-phonon scattering, and its influence on carrier mobility including both optical phonons (OP) and acoustic phonons (AP). The performances of GNRFETs are investigated in detail considering the third nearest neighbour tight-binding approximation. The low-field mobility is extracted in the presence of AP and OP as a function of nanoribbon width and length, from which the diffusive/ballistic limit of operation in GNRFETs is determined.
Mobility in semiconducting graphene nanoribbons: Phonon, impurity, and edge roughness scattering
Physical Review B, 2008
The transport properties of carriers in semiconducting graphene nanoribbons are studied by comparing the effects of phonon, impurity, and line-edge roughness scattering. It is found that scattering from impurities located at the surface of nanoribbons, and from acoustic phonons are as important as line edge roughness scattering. The relative importance of these scattering mechanisms varies with the temperature, Fermi level location, and the width of the ribbons. Based on the analysis, strategies for improvement of low-field mobility are described.
Disorder-induced variability of transport properties of sub-5 nm-wide graphene nanoribbons
Solid-State Electronics, 2013
Transport properties of sub-5 nm-wide graphene nanoribbons (GNRs) are investigated by using atomistic non-equilibrium Green's function (NEGF) simulations and semiclassical mobility simulations of large ensembles of randomly generated nanoribbons. Realistic GNRs with dimensions targeting the 12 nm CMOS node are investigated by accounting for edge defects, vacancies and potential fluctuations.
Influence of substrate type and quality on carrier mobility in graphene nanoribbons
Journal of Applied Physics, 2013
We report the results of a thorough numerical study on carrier mobility in graphene nanoribbons (GNRs) with the widths from 250nmdownto250 nm down to 250nmdownto1 nm, with a focus on the influence of substrate type (SiO 2 , Al 2 O 3 , HfO 2 , and h-BN) and substrate quality (different interface impurity densities) on GNR mobility. We identify the interplay between the contributions of Coulomb and surface optical phonon scattering as the crucial factor that determines the optimum substrate in terms of carrier mobility. In the case of high impurity density ($10 13 cm À2 ), we find that HfO 2 is the optimum substrate irrespective of GNR width. In contrast, for low impurity density (10 10 cm À2 ), h-BN offers the greatest enhancement, except for nanoribbons wider than $200 nm for which the mobility is highest on HfO 2 . V C 2013 AIP Publishing LLC. [http://dx.
Phonon transport simulations in low-dimensional, disordered graphene nanoribbons
2015 IEEE 15th International Conference on Nanotechnology (IEEE-NANO), 2015
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Full band assessment of phonon-limited mobility in graphene nanoribbons
2010
We present a full band investigation of electronphonon interaction in Graphene NanoRibbons (GNRs) by exploiting a tight-binding description within the deformation potential approximation. We show that a full band approach is required to obtain accurate results: mobility as high as 800 cm 2 /Vs at room temperature can be achieved for 1 nm-wide ribbons, more than one order of magnitude higher than that obtainable in silicon nanowires, but still not enough to ensure ballistic transport in GNR-based devices.
An Analytical Model for Line-Edge Roughness Limited Mobility of Graphene Nanoribbons
IEEE Transactions on Electron Devices, 2011
The electronic properties of graphene nanoribbons (GNRs) in the presence of line-edge roughness scattering are studied. The mobility, conductivity, mean free path, and localization length of carriers are analytically derived using an effective mass model for the band structure. This model provides a deep insight into the operation of armchair GNR devices in the presence of line-edge roughness. The effects of geometrical and roughness parameters on the electronic properties of GNRs are estimated assuming a diffusive transport regime. However, in the presence of disorder, localization of carriers can occur, which can significantly reduce the conductance of the device. The effect of localization on the conductance of rough nanoribbons and its dependences on the geometrical and roughness parameters are analytically studied. Since this regime is not suitable for the operation of electronic devices, one can employ these models to obtain critical geometrical parameters to suppress the localization of carriers in GNR devices.