Trilayer Graphene Nanoribbon Research Articles

Performance Analysis of Electrochemical Detection Platform for DNA Hybridization Using TGN-Based Nanobiosensor

Trilayer graphene nanoribbon (TGN) has great potential in related biomedical applications such as drug and gene delivery and deoxyribonucleic acid (DNA) sensing. The performance of a biosensor based on a liquid gate TGN field effect transistor (Lg-TGNFET) to different DNA cancentrations and adsorption effect on the sensing parameters are analytically investigated in this research. Also, the energy band structure, density of states, carrier concentration, electrical conductance and caused electrical response on TGN as a detection element are studied considering the spin–orbit coupling effect, in which significant current change of the TGN-based biosensor is observed after exposure to DNA different values. DNA concentration as a function of gate voltage is assumed and sensing factor is defined. The results of this research confirm that the current of the biosensor is decreased and Vg-min is obviously left-shifted by increasing value of DNA concentration, suggesting that DNA molecules n-dopes the TGN film. In order to verify the accuracy of the TGN-based biosensor, it is compared with recent analytical and experimental reports on DNA biosensors. The proposed biosensor with high specificity and sensitivity exposes higher current compared to that of monolayer graphene counterpart for analogous ambient conditions.

Investigating the Semi-Analytical Models of Momentum Relaxation Mean Free Time and Path and Ionization Coefficient of Trilayer Graphene Nanoribbon- Based FETs

Trilayer graphene nanoribbon as a superlative semiconductor promises potential applications in the diodes, FETs, gas and biosensors. It is a suitable candidate for nanoelectronic applications due to attractive electronic, mechanical, thermoelectric and optoelectronics properties. The aim of the present paper is to analytically investigate the momentum relaxation mean free time and path and also ionization coefficient of trilayer graphene nanoribbon in nanoscale FETs. The models are derived based on energy band structure and calculating the effective mass, carrier velocity and scattering rate. Furthermore, the effects of interlayer potential energies, temperature and potential difference of layers are also taken into account on the modeled parameters. As a result, the obtained results and findings of this research are in rational agreement with published data, in terms of value and trend. The results and figures of merit for the proposed device showed a promising performance for transistor applications.

Contact Effect On Twisted Graphene Based Schottky Transistor

Owing to the exceptional electrical properties of different one dimensional (1D) classifications of graphene structure such as graphene nanoribbon (GNR) and twisted graphene (TWG) led to a revolution in nanoelectronic researche and applications. Thus, these materials have been extensively explored in nanoelectronics science and materials. This paper is focused on GNR and TWG junction as metal-semiconductor-metal (MSM) in the form of a transistor. The wave vectors of TWG and GNR based on the geometrical effects are discussed. By considering 1D potential barrier at the junction of TWG as a semiconducting region and GNR as a metallic region, the transmission probability is calculated. Then, the I–V characteristics of GNR-TWG Schottky transistor based on quantum tunneling effect arepresented and discussed, as well. The performance of GNR-TWG Schottky transistor under variation of gate-source voltage, channel length, number of twists, width of GNR, and temperature are investigated. It is concluded that increment in number of twists and width of GNR lead to increasing the drain current and threshold voltage. Finally, comparison study with graphene nanoscroll (GNS) Schottky transistor, trilayer graphene nanoribbon (TGNR) Schottky transistor, and reported experimental data are performed and results represent that GNR-TWG Schottky transistor has larger drain current than these works.

Effect of solution pH and adsorbent concentration on the sensing parameters of TGN‐based electrochemical sensor

The response of trilayer graphene nanoribbon (TGN)-based ion-sensitive field-effect transistor (ISFET) to different pH solutions and adsorption effect on the sensing parameters are analytically studied in this research. The authors propose a TGN-based sensor to electrochemically detect pH. To this end, absorption effect on the sensing area in the form of carrier concentration, carrier velocity, and conductance variations are investigated. Also, the caused electrical response on TGN as a detection element is analytically proposed, in which significant current decrease of the sensor is observed after exposure to high pH values. In order to verify the accuracy of the model, it is compared with recent reports on pH sensors. The TGN-based pH sensor exposes higher current compared to that of carbon nanotube (CNT) counterpart for analogous ambient conditions. While, the comparative results demonstrate that the conductance of proposed model is lower than that of monolayer graphene-counterpart for equivalent pH values. The results confirm that the conductance of the sensor is decreased and Vg-min is obviously right-shifted by increasing value of pH. The authors demonstrate that although there is not the experimental evidence reported in the part of literature for TGN sensor, but the model can assist in comprehending experiments involving nanoscale pH sensors.

Investigating the Mobility of Trilayer Graphene Nanoribbon in Nanoscale FETs

The aim of the present paper is to investigate the scaling behaviors of charge carrier mobility as one of the most remarkable characteristics for modeling of nanoscale field-effect transistors (FETs). Many research groups in academia and industry are contributing to the model development and experimental identification of multi-layer graphene FET-based devices. The approach in the present work is to provide an analytical model for carrier mobility of tri-layer graphene nanoribbon (TGN) FET. In order to do so, one starts by identifying the analytical modeling of TGN carrier velocity and ballistic conductance. At the end, a model of charge carrier mobility with numerical solution is analytically derived for TGN FET, in which the carrier concentration, temperature and channel length characteristics dependence are highlighted. Moreover, variation of band gap and gate voltage during the proposed device operation and its effect on carrier mobility is investigated. To evaluate the nanoscale FET performance, the carrier mobility model is also adopted to obtain the I–V characteristics of the device. In order to verify the accuracy of the proposed analytical model for TGN mobility, it is compared to the existing experimental data, and a satisfactory agreement is reported for analogous ambient conditions. Moreover, the proposed model is compared with the published data of single-layer graphene and bi-layer graphene, in which the obtained results demonstrate significant insights into the importance of charge carrier mobility impact in high-performance TGN FET. The work presented here is one step towards an applicable model for real-world nanoscale FETs.

Engineer-able optical properties of trilayer graphene nanoribbon

Graphene with a single atomic layer of carbon indicates two-dimensional behavior which plays an important role in sensor application, because of its high surface-to-volume ratio. Its interesting optical properties lead to low-cost and accurate optical devices as well. In the presented work trilayer graphene nanoribbon (TGN) with focus on its optical property for different incident wave lengths in the presence of applied voltage is explored. In low bias condition the optical conductance is modeled and dielectric constant and refractive index based on the estimated conductance are calculated theoretically; finally the obtained results are investigated numerically. Controllable optical properties supported by applied voltage on TGN are proved. Consequently, the proposed model indicates TGN as a possible candidate on surface plasmon based sensors, which needs to be explored.

Trilayer Graphene Nanoribbon Field Effect Transistor Analytical Model

The approaching scaling of Field Effect Transistors (FETs) in nanometer scale assures the smaller dimension, low-power consumption, low energy delay production, and high density as well as high speed in processor. Trilayer graphene nanoribbon with different stacking arrangements (ABA and ABC) indicates different electrical properties. Based on this theory, ABA-stacked trilayer graphene nanoribbon application as a field effect transistor channel is investigated in this study. The energy band structure of ABA-stacked trilayer graphene nanoribbon in the presence of a perpendicular electric field using a tight-binding model is presented, and the effect of applied voltage on the curvature of the E-K graph is analytically studied. Moreover, an analytical model of carrier statistics for ABA-stacked trilayer graphene nanoribbon in corporation with a numerical solution is presented and current-voltage characteristic of trilayer graphene nanoribbon FET as a one-dimensional device is explored. In fact, the proposed model can be applied as a useful tool to optimize the nanoscale FET based device performance. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4698

Carrier Velocity in High-Field Transport of Trilayer Graphene Nanoribbon Field Effect Transistor

Carrier velocity is one of the most significant characteristics for analytical modeling of field effect transistor based devices. The aim of the present paper is to evaluate the scaling behaviours of carrier velocity in trilayer graphene nanoribbon as a function of electron density, normalized Fermi energy and electric field in the degenerate and non-degenerate regimes. To this end, we derive an analytical model of carrier velocity with numerical solution for trilayer graphene nanoribbon field effect transistor in which the temperature and carrier concentration characteristics dependence is highlighted. Moreover, to determine the trilayer graphene nanoribbon field effect transistor performance the carrier velocity model is adopted to derive the current-voltage characteristics of the device. The simulated results proffer remarkable insights into the importance of carrier velocity impact in high performance trilayer graphene nanoribbon field effect transistor. We demonstrate that although there is no experimental evidence reported in the literature for carrier velocity of trilayer graphene nanoribbon, the proposed model can assist in comprehending experiments involving nanoscale field effect transistors.

The effect of torsional deformation on thermal conductivity of mono-, bi- and trilayer graphene nanoribbon

Physical deformation and geometrical change of a low dimensional nanostructure influence the phonon transport leading to appreciable changes in the thermal characteristics. In this paper, we report the calculation of the thermal conductivity of twisted graphene nanoribbon (GNR) using nonequilibrium molecular dynamics (NEMD). A reduction in the value of thermal conductivity of GNR is observed with an increase in the angle of twist. It is observed that the value of thermal conductivity of twisted GNR is dependent on the length of GNR and the temperature at which physical deformation is taking place. Comparing with monolayer GNR, the reduction in the thermal conductivity of bilayer and trilayer GNR is less due to the interactions between the adjacent layers. Analysis of the phonon transport in twisted graphene implies that the reduced thermal conductivity of twisted graphene nanoribbon is due to the phonon softening of acoustic phonon modes.

Quantum confinement effect on trilayer graphene nanoribbon carrier concentration

In this study, one-dimensional vision of carrier movement based on the band structure of trilayer graphene nanoribbon in the presence of a perpendicular electric field is employed. An analytical model of ABA-stacked trilayer graphene nanoribbon carrier statistics as a fundamental parameter of field effect transistor (FET) in corporation with a numerical solution is presented in the degenerate and non-degenerate limits. The simulated results based on the presented model indicate that the model can be approximated by degenerate and non-degenerate approximations in some numbers of normalised Fermi energy. Analytical model specifies that carrier concentration in degenerate limit is strongly independent of normalised Fermi energy; however, in the non-degenerate limit, it is a strong function of normalised Fermi energy. The proposed model is then compared with other types of graphene. As a result, the developed model can assist in comprehending experiments involving trilayer graphene nanoribbon FET-based devices.

Analytical modeling of trilayer graphene nanoribbon Schottky-barrier FET for high-speed switching applications

Recent development of trilayer graphene nanoribbon Schottky-barrier field-effect transistors (FETs) will be governed by transistor electrostatics and quantum effects that impose scaling limits like those of Si metal-oxide-semiconductor field-effect transistors. The current–voltage characteristic of a Schottky-barrier FET has been studied as a function of physical parameters such as effective mass, graphene nanoribbon length, gate insulator thickness, and electrical parameters such as Schottky barrier height and applied bias voltage. In this paper, the scaling behaviors of a Schottky-barrier FET using trilayer graphene nanoribbon are studied and analytically modeled. A novel analytical method is also presented for describing a switch in a Schottky-contact double-gate trilayer graphene nanoribbon FET. In the proposed model, different stacking arrangements of trilayer graphene nanoribbon are assumed as metal and semiconductor contacts to form a Schottky transistor. Based on this assumption, an analytical model and numerical solution of the junction current–voltage are presented in which the applied bias voltage and channel length dependence characteristics are highlighted. The model is then compared with other types of transistors. The developed model can assist in comprehending experiments involving graphene nanoribbon Schottky-barrier FETs. It is demonstrated that the proposed structure exhibits negligible short-channel effects, an improved on-current, realistic threshold voltage, and opposite subthreshold slope and meets the International Technology Roadmap for Semiconductors near-term guidelines. Finally, the results showed that there is a fast transient between on-off states. In other words, the suggested model can be used as a high-speed switch where the value of subthreshold slope is small and thus leads to less power consumption.

The Effect of Applied Voltage on the Carrier Effective Mass in ABA Trilayer Graphene Nanoribbon

Density of states which is an important parameter for the carrier statistics study of Trilayer Graphene Nanoribbon with ABA stacking is modeled in this paper. Analytical model for the density of states of ABA trilayer graphene nanoribbon is proposed and a numerical solution is obtained. In addition, applied voltage effect on carrier effective mass is simulated. The simulation results indicate that by increasing the applied voltage, the carrier effective mass (m?) increases and thus to obtain equal number of electrons and holes, the location of the intrinsic Fermi level will be moved far from the band gap centre.

CHANNEL CONDUCTANCE OF ABA STACKING TRILAYER GRAPHENE NANORIBBON FIELD-EFFECT TRANSISTOR

In this paper, our focus is on ABA trilayer graphene nanoribbon (TGN), in which the middle layer is horizontally shifted from the top and bottom layers. The conductance model of TGN as a FET channel is presented based on Landauer formula. Besides the good reported agreement with experimental study lending support to our model, the presented model demonstrates that minimum conductivity increases dramatically by temperature. It also draws parallels between TGN and bilayer graphene nanoribbon, in which similar thermal behavior is observed. Maxwell–Boltzmann approximation is employed to form the conductance of TGN near the neutrality point. Analytical model in degenerate regime in comparison with reported data proves that TGN-based transistor will operate in degenerate regime like what we expect in conventional semiconductors. Moreover, our model confirms that in similar condition, the conductivity of TGN is less than bilayer graphene nanoribbon as reported in some experiments.