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Puczkarski P, Wu Q, Sadeghi H, Hou S, Karimi A, Sheng Y, Warner JH, Lambert CJ, Briggs GAD, Mol JA. Low-Frequency Noise in Graphene Tunnel Junctions. ACS NANO 2018; 12:9451-9460. [PMID: 30114902 DOI: 10.1021/acsnano.8b04713] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Graphene tunnel junctions are a promising experimental platform for single molecule electronics and biosensing. Ultimately their noise properties will play a critical role in developing these applications. Here we report a study of electrical noise in graphene tunnel junctions fabricated through feedback-controlled electroburning. We observe random telegraph signals characterized by a Lorentzian noise spectrum at cryogenic temperatures (77 K) and a 1/ f noise spectrum at room temperature. To gain insight into the origin of these noise features, we introduce a theoretical model that couples a quantum mechanical tunnel barrier to one or more classical fluctuators. The fluctuators are identified as charge traps in the underlying dielectric, which through random fluctuations in their occupation introduce time-dependent modulations in the electrostatic environment that shift the potential barrier of the junction. Analysis of the experimental results and the tight-binding model indicate that the random trap occupation is governed by Poisson statistics. In the 35 devices measured at room temperature, we observe a 20-60% time-dependent variance of the current, which can be attributed to a relative potential barrier shift of between 6% and 10%. In 10 devices measured at 77 K, we observe a 10% time-dependent variance of the current, which can be attributed to a relative potential barrier shift of between 3% and 4%. Our measurements reveal a high sensitivity of the graphene tunnel junctions to their local electrostatic environment, with observable features of intertrap Coulomb interactions in the distribution of current switching amplitudes.
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Affiliation(s)
- Paweł Puczkarski
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Qingqing Wu
- Department of Physics , Lancaster University , Bailrigg , Lancaster LA1 4YB , United Kingdom
| | - Hatef Sadeghi
- Department of Physics , Lancaster University , Bailrigg , Lancaster LA1 4YB , United Kingdom
| | - Songjun Hou
- Department of Physics , Lancaster University , Bailrigg , Lancaster LA1 4YB , United Kingdom
| | - Amin Karimi
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Yuewen Sheng
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Jamie H Warner
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Colin J Lambert
- Department of Physics , Lancaster University , Bailrigg , Lancaster LA1 4YB , United Kingdom
| | - G Andrew D Briggs
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Jan A Mol
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
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Liu B, Zhu W, Gunapala SD, Stockman MI, Premaratne M. Open Resonator Electric Spaser. ACS NANO 2017; 11:12573-12582. [PMID: 29087690 DOI: 10.1021/acsnano.7b06735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The inception of the plasmonic laser or spaser (surface plasmon amplification by stimulated emission of radiation) concept in 2003 provides a solution for overcoming the diffraction limit of electromagnetic waves in miniaturization of traditional lasers into the nanoscale. From then on, many spaser designs have been proposed. However, all existing designs use closed resonators. In this work, we use cavity quantum electrodynamics analysis to theoretically demonstrate that it is possible to design an electric spaser with an open resonator or a closed resonator with much weak feedback in the extreme quantum limit in an all-carbon platform. A carbon nanotube quantum dot plays the role of a gain element, and Coulomb blockade is observed. Graphene nanoribbons are used as the resonator, and surface plasmon polariton field distribution with quantum electrodynamics features can be observed. From an engineering perspective, our work makes preparations for integrating spasers into nanocircuits and/or photodynamic therapy applications.
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Affiliation(s)
- Bobo Liu
- Advanced Computing and Simulation Laboratory (AχL), Department of Electrical and Computer Systems Engineering, Monash University , Clayton, Victoria 3800, Australia
| | - Weiren Zhu
- Department of Electronic Engineering, Shanghai Jiao Tong University , Shanghai 200240, People's Republic of China
| | - Sarath D Gunapala
- Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California 91109, United States
| | - Mark I Stockman
- Center for Nano-Optics and Department of Physics and Astronomy, Georgia State University , Atlanta, Georgia 30303, United States
| | - Malin Premaratne
- Advanced Computing and Simulation Laboratory (AχL), Department of Electrical and Computer Systems Engineering, Monash University , Clayton, Victoria 3800, Australia
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Conductance fluctuations in high mobility monolayer graphene: Nonergodicity, lack of determinism and chaotic behavior. Sci Rep 2016; 6:33118. [PMID: 27609184 PMCID: PMC5016828 DOI: 10.1038/srep33118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/19/2016] [Indexed: 11/20/2022] Open
Abstract
We have fabricated a high mobility device, composed of a monolayer graphene flake sandwiched between two sheets of hexagonal boron nitride. Conductance fluctuations as functions of a back gate voltage and magnetic field were obtained to check for ergodicity. Non-linear dynamics concepts were used to study the nature of these fluctuations. The distribution of eigenvalues was estimated from the conductance fluctuations with Gaussian kernels and it indicates that the carrier motion is chaotic at low temperatures. We argue that a two-phase dynamical fluid model best describes the transport in this system and can be used to explain the violation of the so-called ergodic hypothesis found in graphene.
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