Full band assessment of phonon-limited mobility in graphene nanoribbons (original) (raw)

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.

Phonon limited transport in graphene nanoribbon field effect transistors using full three dimensional quantum mechanical simulation

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.

Physical insights on graphene nanoribbon mobility through atomistic simulation

We present an investigation of the main mechanisms which limit mobility in GNR-FETs, by means of atomistic simulations based on the NEGF formalism. In particular, we focus on i) line edge roughness (LER), ii) single defects; iii) ionized impurities, iv) acoustic and optical phonons. Results show that the effect of ionized impurities is negligible, while phonons, LER and defects largely limits carrier mobility, especially for narrower GNRs.

On the identification of pristine and defected graphene nanoribbons by phonon signatures in the electron transport characteristics

Inspired by recent experiments where electron transport was measured across graphene nanoribbons (GNR) suspended between a metal surface and the tip of a scanning tunneling microscope [Koch et al., Nat. Nanotechnol. 7, 713 (2012)], we present detailed first-principles simulations of inelastic electron tunneling spectroscopy (IETS) of long pristine and defected armchair and zigzag nanoribbons under a range of charge carrier conditions. For the armchair ribbons we find two robust IETS signals around 169 and 196 mV corresponding to the D-and G-modes of Raman spectroscopy as well as additional fingerprints due to various types of defects in the edge passivation. For the zigzag ribbons we show that the spin state strongly influences the spectrum and thus propose IETS as an indirect proof of spin polarization.

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.

Impact of the Electron-Phonon Interactions on the Polaron Dynamics in Graphene Nanoribbons

The journal of physical chemistry. A, 2016

The influence of the electron-phonon (e-ph) interactions on the filed-included polaron dynamics in armchair graphene nanoribbons (GNRs) is theoretically investigated in the scope of a two-dimensional tight-binding model. The results show that the localization of the polaronic charge increases when the strength of e-ph coupling also increases. Consequently, the polaron saturation velocity decreases for higher e-ph coupling strengths. Interestingly, the interplay between the e-ph coupling strength and the GNR width changes substantially the polaron dynamics properties.

Identification of pristine and defective graphene nanoribbons by phonon signatures in the electron transport characteristics

Physical Review B, 2015

Inspired by recent experiments where electron transport was measured across graphene nanoribbons (GNR) suspended between a metal surface and the tip of a scanning tunneling microscope [Koch et al., Nat. Nanotechnol. 7, 713 (2012)], we present detailed first-principles simulations of inelastic electron tunneling spectroscopy (IETS) of long pristine and defected armchair and zigzag nanoribbons under a range of charge carrier conditions. For the armchair ribbons we find two robust IETS signals around 169 and 196 mV corresponding to the D-and G-modes of Raman spectroscopy as well as additional fingerprints due to various types of defects in the edge passivation. For the zigzag ribbons we show that the spin state strongly influences the spectrum and thus propose IETS as an indirect proof of spin polarization.

Phonon transport simulations in low-dimensional, disordered graphene nanoribbons

2015 IEEE 15th International Conference on Nanotechnology (IEEE-NANO), 2015

The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription.

Electron Transport Parameters Study for Transition Metal-Doped Armchair Graphene Nanoribbon via Acoustical Phonon Interactions

Journal of Electronic Materials, 2017

Electron transport parameters such as electron effective mass, Fermi velocity of an electron and electron mobility are calculated for transition metal [manganese (Mn), cobalt (Co)]-doped armchair graphene nanoribbon (aGNR) via polar acoustical phonon [piezoelectric (PZ)] scattering and acoustical deformation potential (ADP) scattering under a high electric field and different doping concentrations. Moreover, the effect of dopant site on these electron transport parameters is also investigated. It is observed that the electron effective mass is reduced significantly in doped aGNR in comparison to pure GNR. It is observed that the net electron mobility contributed by both ADP and PZ mechanisms for Mn-doped aGNR as well as Co-doped aGNR varies in similar fashion as semiconductors wherein the net electron mobility (ADP + PZ) for Mn-doped aGNR is greater than that for the Co-doped graphene nanoribbon. Moreover, it is found that there is no impact of variation in dopant site on the electron transport parameters considered in this study.