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Doping-induced giant rectification and negative differential conductance (NDC) behaviors in zigzag graphene nano-ribbon junction
摘要： By p-type and n-type doping on the electrode edges of V-notched zigzag graphene nano-ribbons (ZGNRs), four V-notched ZGNR-based PN-junctions are designed theoretically. The electronic transport properties of the doped and un-doped V-notched ZGNRs are studied applying non-equilibrium Green’s function method combined with the density functional theory. The numerical results show that, the doped systems are less conductive than the un-doped system, because after doping the transition states become localized. To our surprise, the ZGNR-based PN-junctions do not show obvious rectification by purely doping the boron atoms and nitrogen atoms on the edges of two ZGNR electrodes respectively. However, after hydrogenated the doped boron atoms and nitrogen atoms, the ZGNR systems present giant rectifications with the maximum rectification ratios up to 106 ～ 107, which attributed to the vanishing of overlap between left-electrode sub-band and right-electrode sub-band in the negative bias regime after the doped boron and nitrogen atoms being hydrogenated. Due to the same reason, the hydrogenated doping systems also show large negative differential conductance behaviors.
关键词： Giant rectification,Negative differential conductance,Graphene nano-ribbon junction,Boron and nitrogen doping
更新于2025-09-23 15:22:29
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Structure determination of substrate influenced silicon nano-ribbon growth
摘要： Using photoelectron diffraction (XPD), photoelectron spectroscopy (XPS), and low energy electron diffraction (LEED), we investigate the structure of silicon nano-ribbons grown on Au(1 1 0). We find that silicon forms two zigzag-terminated hexagonal chains along the [1 1 0]-substrate direction, while the gold substrate forms a bulk-typed surface reconstruction after silicon evaporation. Only two missing rows along the [1 1 0]-direction remain partially in their original structure at the Si/Au interface. Unlike silicon nano-ribbon formation on Ag(1 1 0), nano-ribbon growth on Au(1 1 0) is strongly substrate influenced by Van-der-Waals interaction and by AuSi bonding formation. This strong interaction leads to a substrate-driven hexagon formation, where the gold atoms are partially integrated into the ribbon structure. Besides the determination of the internal silicon nano-ribbon structure, we identify the origin of the two chemically shifted silicon components in the XPS spectra by deconvolving the diffraction pattern.
关键词： Photoelectron spectroscopy,Hexagonal chains,Nano-ribbon,Silicon,Photoelectron diffraction
更新于2025-09-23 15:21:01
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Frequency-tunable logic gates in graphene nano-waveguides
摘要： In this study, simple basic plasmonic logic gates of XOR, OR, and NOT based on graphene nano-ribbon resonators coupled to properly designed arrangements of nano-waveguides, as input and output logic ports, are demonstrated. The operation of the structures as frequency selective components is based on the propagation of edge modes in nano-waveguides and coupling to nano-ribbon resonators located in appropriate locations. The gates performance is investigated through analytic approaches and verified numerically using the finite difference time domain method. Typical extinction ratio of about 8 dB between ON and OFF logic states has been attained. According to the fantastic feature of voltage-dependent chemical potential of graphene conductivity, the characteristics of the structures can be actively manipulated. These sub-wavelength plasmonic components can be employed extensively in terahertz demanded applications.
关键词： Nano-ribbon resonator,Nano-waveguide,Logic gate,Plasmonic component,Graphene-based component,Terahertz spectra
更新于2025-09-19 17:13:59
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Modeling, analysis, and simulation of millimeter-wave Graphene Nano-Ribbon (GNR) cylindrical coupled transmission line
摘要： This paper discusses an analytical formulation for extracting electrical parameters of the Graphene Nano-Ribbon cylindrical Transmission Line (TL), and compares the results with numerical ones obtained through analysis of the same structure using the TLM method in the mm-wave frequency range. To assess the validity of this model, our proposed numerical approach and the simulated models have been compared, and a good agreement has been obtained in this comparison.
关键词： Cylindrical coordinate,Graphene Nano-Ribbon,Transmission line modeling
更新于2025-09-19 17:13:59
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Terahertz plasmonic SWAP and Fredkin gates utilizing graphene nano-ribbon waveguides
摘要： In this paper, terahertz plasmonic SWAP and Fredkin gates using the Si–SiO2-air–graphene–air structure deposited on the SiO2/Si substrate are presented and numerically studied. The presented terahertz plasmonic SWAP gate is composed of a symmetric Y-junction, two all-pass microring resonators, and a double series-coupled microring resonator, and the proposed terahertz plasmonic Fredkin gate comprises a three-arm Y-junction, three all-pass microring resonators, and a double series-coupled microring resonator. By flexibly adjusting graphene’s chemical potential in rings, microring resonators’ resonant states produce the change, then logic operations of SWAP and Fredkin gates can be correctly executed. Simulation results show that our designed terahertz plasmonic SWAP and Fredkin gates exhibit excellent extinction ratio and crosstalk. For the designed terahertz plasmonic SWAP gate, the extinction ratio can be greater than 20.92 dB and the crosstalk can be less than ?21.38 dB. With input logic states of ‘000’, ‘001’, ‘010’, ‘011’, ‘100’, ‘101’, ‘110’, and ‘111’, the designed terahertz plasmonic Fredkin gate has a minimum extinction ratio of 21.65 dB and a maximum crosstalk of ?21.15 dB.
关键词： Integrated optics,Logic gates,Waveguide,Graphene nano-ribbon,Plasmonic
更新于2025-09-19 17:13:59
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Thermal Stability Analysis of Graphene Nano-ribbon Interconnect and Applicability for Terahertz Frequency
摘要： In this paper, we have studied the thermal stability of GNR and Cu interconnects for terahertz frequency range. The top-contact (TC) and side-contact (SC) GNR interconnects are analyzed for stability, RC-delay, and power consumption at different lengths (10 lm, 50 lm and 100 lm) and different chip operating temperatures (233 K, 300 K and 378 K). The RC-delay and power consumption are analyzed with the help of transmission line model (TLM) using 16nm PTM-HP standard CMOS model. In our analysis, we have shown that the RC-time constant for SC-GNR is (cid:2) e3(cid:3)7T(cid:4) and (cid:2) e2(cid:3)6T(cid:4) less than that of TC-GNR and Cu interconnects. Similarly, we have shown that the power consumption for SC-GNR is (cid:2) e4(cid:3)7T(cid:4) and (cid:2) e2(cid:3)5T(cid:4) less than that of TC-GNR and Cu. In terms of stability, SC-GNR interconnect is more stable at higher frequency range ( [ 1012 Hz) compared with TC-GNR and Cu for 10 lm interconnect length and three different chip operating temperatures.
关键词： Top-contact GNR (TC-GNR),Interconnects,Graphene nano-ribbon (GNR),Stability,Side-contact GNR (SC-GNR)
更新于2025-09-12 10:27:22