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We propose a spin device based on a T-shaped graphene junction (TGJ) in which a ferromagnetic insulator and a metallic gate are deposited on the sidearm. Spin transport properties of the TGJ are studied by using the Green's function method. It is found that spin-polarized transport can be achieved both far away from and near the Dirac point. The spin polarization far away from the Dirac point is correlated with the quasi-bound states in the junction, while the spin polarization near the Dirac point is due to the destruction of edge states. By varying the strength of the potential, i.e., the gate voltage on the sidearm, the spin polarization can be tuned quasi-periodically from -100% to 100%. In addition, the size of the sidearm also shows obvious influence on the spin polarization of TGJ. [ABSTRACT FROM AUTHOR]

Recently, the AA-stack bilayer graphene nanoribbon (BGN) with a closed edge is observed in experiment. This new type of GN, we called folded GN (FGN), can be formed by folding a monolayer GN (MGN). Electron transport of the folded structures with different edges is studied. The FGNs show unique transport properties different from those of MGNs and BGNs. A metallic MGN with armchair edge (MAGN) is still metallic after folding. However, a semiconducting MAGN can be either semiconducting or metallic after folding, which depends on the width of MAGN and strength of interlayer coupling in the folded structure. The energy gap decreases with the increase of the coupling strength or width. As to the MGNs with zigzag edge (MZGNs), after folding they exhibit interesting conductance characteristics. The conductance steps around the Dirac point are even multiple of G0=2e2/h, while other conductance steps are odd multiple of G0. It indicates that the electron transport around the Dirac point in zigzag-edged FGNs (FZGNs) is similar to that in zigzag-edged BGNs (BZGNs), while electron transport far from the Dirac point is similar to that in zigzag-edged MGNs (MZGNs). [ABSTRACT FROM AUTHOR]

Dumbbell silicene, a stable allotrope of low-buckled (LB) silicene containing both sp2 and sp3 hybridized states, is a new topic in current graphene-derived material research community. In this paper, we performed a comprehensive study on the thermoelectric property of dumbbell silicene nanoribbons (DB-SNRs) via utilizing nonequilibrium Green's function (NEGF) method as implemented in the density functional based tight-binding (DFTB) framework. Our results show that DB-SNRs present superb electronic transport properties, e.g., the room temperature Seebeck coefficient could approach 2.11 mV/K (about 80% larger than that of LB silicene). A unique step-like width dependence of phononic thermal conductance is also observed in Z-DB-SNRs, which mainly attributes to localized phonon modes raised from the edged sp3 Si atoms. Based on the electronic and phononic transport coefficient, the thermoelectric performance of DB-SNRs is predicted and the stable ZT value at room temperature is found to be about 0.7(0.3) and 0.6(0.2) for A-DN-SNRs and Z-DB-SNRs with p(n)-type doping. Such thermoelectric performance could be further improved by increasing the temperature. The findings presented in this work shed light on the thermoelectric property of DB-SNRs and could provide helpful guideline for designing and fabricating of future Si-based thermoelectric devices. [ABSTRACT FROM AUTHOR]

We theoretically investigate the ballistic thermoelectric performance of graphene nanoribbons with surface roughness using the nonequilibrium Green's function method. The results show that the surface roughness could dramatically reduce the thermal conductance of graphene nanoribbons, and thus lead to the boosting of thermoelectric performance of graphene (the figure of merit can be as high as 3.7 at room temperature). Meanwhile, the electron transport properties of different edged rough graphene nanoribbons exhibit distinctive anisotropic behaviors, i.e., the thermal power of armchair edged nanoribbons significantly increases, while that of zigzag edged remains nearly unchanged, which is mainly attributed to the edge effect. The findings presented in this paper qualify surface roughness as an efficient approach to enhance the thermoelectric performance of graphene nanoribbons. [ABSTRACT FROM AUTHOR]

Abstract: Tin disulfide (SnS2) nanosheets have attracted tremendous attention owing to their unique electronic and optoelectronic properties. However, practical photodetector applications based on SnS2 are usually limited by low responsiveness and fast electron‐hole recombination. Fortunately, graphene exhibits attractive potential for optoelectronic owing to its intrinsic high carrier mobility conductivity, large surface area, and mechanical flexibility. Herein, we have prepared SnS2/graphene heterostructures by a facile hydrothermal method. The as‐prepared SnS2/graphene heterostructures are used to fabricate photodetectors on both SiO2/Si and flexible polyethylene terephthalate (PET) substrates, and the performances of the photodetectors have been investigated under wavelengths ranging from 365 to 577 nm. The results show that as‐fabricated photodetector on SiO2/Si substrate has achieved excellent stability; meanwhile, the photocurrent densities of SnS2/graphene on PET substrate are not influenced by the external bending representing an excellent mechanical stress stability. All of the experimental results propose that the SnS2/graphene heterostructures possess great potential in light detection. [ABSTRACT FROM AUTHOR]

In the paper, the graphene oxide (GO) prepared by modified Hummers method was characterized by Raman spectrum, Fourier transform infrared spectrum (FTIR), and Atomic Force Microscopy (AFM). Using Kelvin Probe Force Microscopy (KPFM), the surface potential of GO was investigated, and it was found that the GO film exhibited the uniform surface potential distribution. The surface potentials at the edges and wrinkles of GO film were much lower than that at the in-plane flat area, which is proposed to be contributed to the bonds’ unsaturated and disorder at these zones. These results provide insight into understanding electronic properties of GO-based composites and devices. [ABSTRACT FROM AUTHOR]

By performing density functional theory calculations, we studied the quantum confinement in charged graphene quantum dots (GQDs), which is found to be clearly edge and shape dependent. It is found that the excess charges have a large distribution at the edges of the GQD. The resulting energy spectrum shift is very nonuniform and hence the Coulomb diamonds in the charge stability diagram vary irregularly, in good agreement with the observed nonperiodic Coulomb blockade oscillation. We also illustrate that the level statistics of the GQDs can be described by a Gaussian distribution, as predicted for chaotic Dirac billiards. [ABSTRACT FROM AUTHOR]

Based on folded graphene nanoribbons, we report a thermal conductance modulator which performs analogous operations as the rheostat in electronic circuits. This fundamental device can controllably and reversibly modulate the thermal conductance by varying the geometric structures and its tuning range can be up to 40% of the conductance of unfolded nanoribbons (∼1 nm wide and 7-15 nm long). Under this modulation, the conductance shows a linearly dependence on the folded angle, while undergoes a transition with the variation of the inter-layer distance. This primary thermal device may have great potential applications for phononic circuits and nanoscale thermal management. [ABSTRACT FROM AUTHOR]

We propose a new allotrope of graphane (named as 'tricycle') with equivalent 4up/2down UUUDUD hydrogenation in each six-carbon ring, which can be considered as the combination of previously proposed 3up/3down chair graphane and stirrup graphane. We find that tricycle graphane is more stable than stirrup graphane and its negative Gibbs free energy (-91 meV/atom) is very close to that of the most stable chair one (-103 meV/atom). Investigations on its vibrational property confirm its dynamical stability. Such a new two-dimensional hydrocarbon may be produced in the process of graphene hydrogenation with a relatively high probability due to its remarkable stability. [ABSTRACT FROM AUTHOR]

The electronic transport properties of hybrid graphene nanoribbons constructed by substituting C atom chain into B (N) atom chain are investigated through using the density functional theory in combination with the nonequilibrium Green's function method. It is found that the hybrid nanoribbon with armchair edge transits from semiconducting to metallic. While the transport properties of hybrid B (N) system with zigzag edge are highly improved with the transmission conductance around the Fermi level increasing to 6G0 (5G0). All these unique transport properties are mainly attributed to the coupling effect between B (N) atoms and C atoms at the interface of hybrid systems, which introduces a pair of bonding and antibonding bands around the Fermi level. The results indicate that such hybrid system is an effective way to modulate the transport properties of graphene nanoribbons. [ABSTRACT FROM AUTHOR]

New and novel 3D hierarchical porous graphene aerogels (HPGA) with uniform and tunable meso-pores (e.g., 21 and 53 nm) on graphene nanosheets (GNS) were prepared by a hydrothermal self-assembly process and an in-situ carbothermal reaction. The size and distribution of the meso-pores on the individual GNS were uniform and could be tuned by controlling the sizes of the Co3O4 NPs used in the hydrothermal reaction. This unique architecture of HPGA prevents the stacking of GNS and promises more electrochemically active sites that enhance the electrochemical storage level significantly. HPGA, as a lithium-ion battery anode, exhibited superior electrochemical performance, including a high reversible specific capacity of 1100 mAh/g at a current density of 0.1 A/g, outstanding cycling stability and excellent rate performance. Even at a large current density of 20 A/g, the reversible capacity was retained at 300 mAh/g, which is larger than that of most porous carbon-based anodes reported, suggesting it to be a promising candidate for energy storage. The proposed 3D HPGA is expected to provide an important platform that can promote the development of 3D topological porous systems in a range of energy storage and generation fields. [ABSTRACT FROM AUTHOR]

We studied the nanoindentation of monolayer graphene by molecular dynamics simulations. It is found that the response of graphene to indentation is deflection dependent. In small deflection range, the response obeys point load model, while large-deflection indentation follows the sphere load model. Hence, we proposed to make sectional fittings and use different response models in different deflection ranges. In this way, a consistent Young's modulus is obtained that is almost independent of the size ratio of intender to graphene and the pretensions of graphene. The calculated Young's modulus is about 1.00 TPa, in good agreement with the experiments. [ABSTRACT FROM AUTHOR]

Point defects engineering in a new type hetero bilayer consisting of graphene and hexagonal boron–nitrogen (h-BN) sheet, including vacancy, substitutional C/B/N doping and the possible combinations of the former two, was theoretically studied using first-principles calculations. The optimized geometry, formation energy, magnetic moment, and electronic property of these systems are discussed. It was found that N vacancy is more likely to form than B vacancy in graphene/h-BN bilayer and their electronic properties exhibit n-type and p-type conductivity, respectively. Divacancy of N and C in hetero bilayer shows high stability and induces direct band gap in up and down spin, respectively. Combined by N substitutional doping in graphene and B vacancy in h-BN layer, this substitution-vacancy combination shows low formation energy and changes the semiconductor property of pristine graphene/h-BN bilayer to metallic. In contrast, the graphene/h-BN bilayer with the combinated defect of C-substitution in B site and C vacancy in graphene shows half-metallic electronic property. The calculated magnetic moments are in reasonable agreement with the available theoretical analysis on atomic charge distribution. This work reveals that the electronic and magnetic properties of graphene/h-BN bilayer can be effectively tuned by above proposed point defects engineering. [ABSTRACT FROM AUTHOR]

A flexible Bi 2 Se 3 /Graphene (BSG) composite paper has been prepared through a simple vacuum filtration method and a thermal reduction together. The BSG composite paper was directly used as anode electrode for lithium-ion batteries, without using any polymer binders or conduction additives. In contrast to the pure Bi 2 Se 3 , the BSG exhibits high reversible lithium ion storage capacities and superior cyclic capacity retention. It proposed that the superior lithium storage performances would be attributed to the special construction of the as-prepared BSG paper, in which the graphene can not only act as conductive network for electrodes, but also act as a frame to alleviate volume expansion or aggregation of Bi 2 Se 3 nanosheets during lithiation/delithiation. The as-prepared BSG paper shows a great potential as an anode materials for flexible Li-ion batteries. [ABSTRACT FROM AUTHOR]

In this work, SnS 2 nanoplates entrapped graphene aerogel has been successfully prepared by simple self-assembly of reduced graphene oxide obtained through mild chemical reduction. Structural and morphological investigations demonstrated that SnS 2 nanoplates are highly dispersed in the three dimensional (3D) porous graphene matrix. When served as anode material for lithium-ion batteries, the electrochemical properties of SnS 2 /graphene aerogel (SnS 2 /GA) were evaluated by galvanostatic discharge–charge tests, cyclic voltammetry and impedance spectroscopy measurement. Compared with pristine SnS 2 , the SnS 2 /GA nanocomposite achieved a much higher initial reversible capacity (1186 mAh g −1 ), superior cyclic stability (1004 mAh g −1 after 60 cycles, corresponding to 84.7% of the initial reversible capacity), as well as better rate capability (650 mAh g −1 at a current density of 1000 mA g −1 ). This significantly improved lithium storage performance can be attributed to the good integration of SnS 2 nanoplates with 3D porous graphene network, which can not only provide much more active sites and easy access for Li ions intercalation, but also prevent the aggregation of SnS 2 nanoplates and facilitate fast transportation of Li ions and surface electrons during the electrochemical process. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) interconnected graphene network embedded with uniformly distributed tin disulfide (SnS 2 ) nanoplates was prepared by a facile two-step method. The microstructures and morphologies of the SnS 2 /graphene nanocomposite (SSG) are experimentally confirmed by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Using the as-prepared SSG as an anode material for lithium batteries, its electrochemical performances were investigated by cyclic voltammograms (CV), charge/discharge tests, galvanostatic cycling performance and AC impedance spectroscopy. The results demonstrate that the as-prepared SSG exhibits excellent cycling performance with a capacity of 1060 mAh g −1 retained after 200 charge/discharge cycles at a current density of 100 mA g −1 , also a superior rate capability of 670 mAh g −1 even at such a high current density of 2000 mA g −1 . This favorable performance can be attributed to the unique 3D interconnected architecture with great electro-conductivity and its intimate contact with SnS 2 . Our results indicate a potential application of this novel 3D SnS 2 /graphene nanocomposite in lithium-ion battery. [ABSTRACT FROM AUTHOR]

Here, novel graphene/TiO 2 nanocomposite has been successfully prepared by loading flocculent-like titanate nanostructure in graphene sheets via hydrothermal method plus a subsequent annealing process. The as-obtained hybrid was characterized by X-ray diffraction, scanning electron microscopy with an energy dispersive spectroscope (EDS), Raman, and UV–vis diffuse reflectance spectra, respectively. The photoelectrochemical activities and photocatalytic degradation performance of methyl orange under the illumination of ultraviolet light were investigated, and the flocculent-like TiO 2 /graphene composites was found to have a superior photocatalytic activity compared to flocculent-like titanate nanostructure and commercial anatase TiO 2 powder, which can be attributed to the improved light absorption and extremely efficient charge separation of the hybrid structure. The results suggest that the as-prepared flocculent-like TiO 2 /graphene composite is a promising photocatalyst for photoelectrochemical hydrogen production and pollution removal. [ABSTRACT FROM AUTHOR]

A simple one-pot green electrodeposition route is presented for the synthesis of ZnO/graphene nanosheets composite. During a electrochemical deposition process, the graphene oxide nanosheets loose oxygen-containing functional group to become graphene nanosheets (GNS), and zinc oxide (ZnO) is also electrochemically deposited on the electrode. Such hybrid microstructure facilitates the charge and ion transport in the electrode, which has been observed by scanning electron microscopy. Besides, the as-prepared ZnO/GNS sample also has been characterized with X-ray powder diffraction and Raman spectra. Moreover, the electrochemical performance of the obtained composite used as supercapacitor electrode is investigated by cyclic voltammerty, galvanostatic charge/discharge, and electrochemical impedance spectra tests. At the current density of 3 Ag −1 , the resulting ZnO/GNS composite exhibits an enhanced specific capacitance of 291 Fg −1 , much larger than that of pure ZnO (118.8 Fg −1 ). [ABSTRACT FROM AUTHOR]

A novel graphene-based three-dimensional (3D) aerogel embedded with two types of functional nanomaterials had been prepared by a facile one-pot hydrothermal process. During the hydrothermal reaction, graphene, TiO 2 nanoparticles and MoS 2 nanosheets were self-assembled into the 3D interconnected networks aerogel, where the uniformly dispersed TiO 2 nanoparticles were densely anchored onto the graphene nanosheets and decorated with the ultrathin MoS 2 nanosheets. The UV–vis DRS and PL spectra measurement shows that the MoS 2 /P25/graphene aerogel exhibits enhanced light absorption and efficient charge separation properties. As a new photocatalyst, the photocatalytic activity was evaluated by photoelectrochemical test and photodegradation methyl orange (MO) under UV irradiation, an improvement of photocurrent was observed, as 6 times higher for MoS 2 /P25/graphene aerogel (37.45 mA/cm 2 ) than pure P25 at +0.6 V, and the fastest photodegradation of MoS 2 /P25/graphene aerogel was found within 15 min. The improved photocatalytic activity is attributed to the porous structure, good electrical conductivity and the maximization of accessible sites of the unique 3D graphene aerogel, the increasing active adsorption sites and photocatalytic reaction centers for the introduction of MoS 2 nanosheets, and the positive synergetic effect between the three components in this hybrid. This work demonstrates that the as-prepared MoS 2 /P25/graphene aerogel may have a great potential application in photoelectrochemical hydrogen production and pollution removal. [ABSTRACT FROM AUTHOR]

Abstract: In this current work, the electrochemical co-deposition of nickel sulfide/electrochemically reduced graphene oxide(ERGO) nanocomposites is presented. During the electrochemical process, the graphene oxide nanosheets loose their hydrophilicity and precipitate onto the electrode. In the meantime, nickel sulfide is also electrochemically deposited on the electrode. The porous structure with ERGO covered by nickel sulfide, which facilitates the charge and ion transport in the electrode, has been observed by a scanning electron microscope. The cycle voltammetry curves as well as the galvanostatic charge/discharge curves of the nickel sulfide/ERGO nanocomposites exhibit distinct pseudocapacitive characteristic. The nanocomposites maintain 66.8% of the initial specific capacitance for the first 500 cycles, and only 4.6% loss of the specific capacitance is experienced for the further 1500 cycles, evidently showing a relatively high cycling stability. The results suggest that the nickel sulfide/ERGO is a promising electrode material for supercapacitors. [Copyright &y& Elsevier]

Highlights: [•] A graphene-based ternary composite was prepared by loading ZnO and CdS nanoparticles in graphene nanosheets via a facile one-step hydrothermal method. [•] The CdS/ZnO/graphene composite demonstrated improved light-harvesting and superior durability photoelectrochemical activity. [•] The ternary composite can hinder the recombination of photo electrons and holes and improve charge transfer to enhance the photocatalytic activity. [Copyright &y& Elsevier]

Abstract: We have successfully fabricated the enhanced 3D hierarchical double porous Co3O4/graphene architecture by employing a simple, facile and inexpensive microwave-assisted method. The ultimately formed hierarchical porous configuration can provide more rapid electrolyte diffusion to the active materials due to macro- and micro-porosity. The Co3O4 nanoparticles (NPs), which are homogeneously distributed on graphene sheets, showed high reversible capacities as well as significantly enhanced cycling performance and high rate capabilities when evaluated as anode for lithium ion battery. The superior performance could be attributed to the unique enhanced 3D hierarchical double porous architecture. Our results opened a new doorway to prepare novel anode architecture for high performance lithium ion batteries. [Copyright &y& Elsevier]

Highlights: [•] Armchair graphene nanoribbon with K edge-adsorption becomes a metal while it is a semiconductor in pristine. [•] The interaction between the K adatom and armchair graphene nanoribbon is purely ionic. [•] K edge-adsorption can suppress the magnetic moment at the impurity site and its vicinity in zigzag graphene nanoribbon. [•] A ferromagnetic state is created when introduce K impurities asymmetry in two sides of zigzag graphene nanoribbon. [ABSTRACT FROM AUTHOR]

Abstract: The photoresponse properties of solution processed graphene oxide (GO) ranged from ultraviolet–visible–near infrared regime are studied. Photoelectrochemical results indicate that the as-prepared GO devices have excellent sensitivity, high-speed and superior reproducibility as a visible and near infrared photodetector. Especially, the responsivity and external quantum efficiency are found to be about 95.8mA/W and 26.2%, respectively, for incident wavelength of 455nm at 0.8V bias voltage. Resulting from the degradation of GO under UV irradiation, the GO devices exhibit unstable photoresponse performance, as well as high UV photosensitivity. [Copyright &y& Elsevier]

Abstract: Using the density functional theory in combination with the nonequilibrium Green’s function method, we investigate the transport properties of zigzag-edged graphene nanoribbons (ZGNRs) with oxygen edge decoration (passivated by the ketone (Cer (C–O–C), denoting as ZGNR-CO and ZGNR-C2O, respectively). We find that both ZGNR-CO and ZGNR-C2O induce the semiconductor-metal transition and enhance the transmission conductance within ‘transparent’ electrodes. However, sandwiched by Au (111) electrodes, Au∣ZGNR − CO∣Au enhances the transport properties while Au∣ZGNR − C2O∣Au depresses the transport properties in comparison with Au∣ZGNR − H∣Au. It is found that the transport properties of the edge oxidized ZGNRs within Au (111) electrodes depend on the electronic states around the Fermi level which determine the number of the effective transport channels. The states of Au∣ZGNR − CO∣Au are delocalized on the edge oxygen atoms as well as the inner edge carbon atoms, introducing extra transport channels. Moreover, in comparison with Au∣ZGNR − H∣Au, the effective transport channels of Au∣ZGNR − CO∣Au increase at given applied bias. However, the states of Au∣ZGNR − C2O∣Au are localized on the ribbon, blocking the effective transport channels. [Copyright &y& Elsevier]

The thermoelectric properties of hybrid graphene/boron nitride nanoribbons (BCNNRs) are investigated using the nonequilibrium Green's function approach. We find that the thermoelectric figure of merit (ZT) can be remarkably enhanced by periodically embedding hexagonal BN (A-BN) into graphene nanoribbons (GNRs). Compared to pristine GNRs, the ZT for armchair-edged BCNNRs with width index 3p + 2 is enhanced 10-20 times, while the ZT of nanoribbons with other widths is enhanced by just 1.5-3 times. As for zigzag-edge nanoribbons, the ZT is enhanced 2-3 times. This improvement comes from the combined increase in the Seebeck coefficient and the reduction in the thermal conductance outweighing the decrease in the electrical conductance. In addition, the effect of the component ratio of h-BN on the thermoelectric transport properties is discussed. These results qualify BCNNRs as a promising candidate for building outstanding thermoelectric devices. [ABSTRACT FROM AUTHOR]

Abstract: We report the effect of bending deformation on the optical and transport properties of zigzag graphene nanoribbons (ZGNRs) induced by the uniaxial strain using the first-principles method combined with non-equilibrium Green''s function. The optical properties of ZGNRs in the region of visible light are almost unchanged under the uniaxial strain, whereas an absorption peak occurs at the infrared region for the bent ZGNRs under the transverses strain. The transport properties of ZGNRs under the transverses strain with the bending angle up to 65° remain almost the same as those of the flat one. The transmission coefficients around the Fermi level only slightly decrease when the bending angle further increases to 72.5°. Moreover, ZGNRs under the longitudinal strain show the same transmission conductance around the Fermi level as that of the flat one. The edge states of ZGNRs still behave as excellent ballistic transport channels under bending deformation, which makes them promising flexible and robust transparent conductors. [Copyright &y& Elsevier]

Abstract: Based on the Anderson tight-binding model, the electronic properties of disordered bilayer graphene are investigated. Our numerical results show that electrons in bilayer graphene with monolayer disorder (MDBG) exhibit a peculiar behavior that is quite different from that in bilayer graphene with bilayer disorder (BDBG). With the increase of disorder, BDBG becomes an insulating disordered two-dimensional (2D) electron system. In the case of monolayer disorder, however, the energy spectrum has strongly localized tail states and a stable extended central state separated by persistent mobility edges which are independent of the disorder strength. This indicates that a metal–insulator transition occurs in the monolayer disorder structure. This is similar to the case in an order–disorder separated quantum film. The results could offer useful information for understanding and manipulating the electronic properties of disordered bilayer graphene. [Copyright &y& Elsevier]

Abstract: Three-terminal nanojunctions based on triangle zigzag edged graphene flakes are proposed and their transport properties are studied. In the solid and hollow triangle graphene junctions, there exist different resonant transmissions due to the different electronic states in the two structures. The quasi-bound states in the solid junction are confined in the inner of the triangle flake, while those in the hollow junction are confined at the zigzag edges. In addition, these states are tightly associated with the size of the triangle flake, thus the resonant transmissions in the triangle graphene junctions can be tuned by the structural size and geometry. [Copyright &y& Elsevier]

Abstract: We study transport properties of two L-shaped graphene nanoribbons (LGNRs) with different corner deformation. It is found that the corner geometry of the L-shaped junction has enormous influence on the electron transport around the Fermi energy. As a triangle graphene flake is added to the inside corner of a metallic right-angle LGNR, a gap appears in the conductance, i.e., the properties of the LGNR transform from metallic to semiconducting. However, as a triangle graphene flake is cut from the deformed semiconducting LGNR, resonant peaks via quasi-bound states exist in the original gap of conductance. The LGNR with deformed inside and outside corners is equivalent to a resonant-tunneling transistor. The quasi-bound states inducing the resonant transmission are confined in the L-shaped junction and strongly dependent on the size of the corner. Thus one can tune the transport properties of LGNR by the structural geometry and size. [Copyright &y& Elsevier]