Ultrafast hot-carrier-dominated photocurrent in graphene

Sun, Dong; Aivazian, Grant; Jones, Aaron M.; Ross, Joel; Yao, Wang; Cobden, David; Xu, Xiaodong

doi:10.1038/nnano.2011.243

Cited by 403 publications

(438 citation statements)

References 34 publications

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“…In addition to the distribution of the NV centres, the transient-current map reflects the potential landscape within the graphene sheet. The long-lived currents have a timescale from picoseconds up to nanoseconds, which exceeds the direct laser-generated carrier dynamics in pristine graphene 8,14,15,33 ( Supplementary Fig. 3).…”

mentioning

confidence: 96%

“…2a). At this position, the electric field is dominated by the built-in potential at the graphene-gold interface 8,14,15,33 . The longlived transient currents (blue-shaded region in Fig.…”

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confidence: 99%

“…To this end, we can take advantage of the excellent optical and electronic properties of graphene 9 , which include good photodetection capabilities 8,[10][11][12][13][14][15] , efficient energy absorption 3 and strong light-matter interactions at the nanoscale 16,17 . In particular, it has been reported recently that, because of graphene's specific properties, the near-field interaction between light emitters and graphene is greatly enhanced as compared to that of conventional metals [2][3][4][5][6] .…”

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Ultrafast electronic readout of diamond nitrogen–vacancy centres coupled to graphene

et al. 2014

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Non-radiative transfer processes are often regarded as loss channels for an optical emitter 1 because they are inherently difficult to access experimentally. Recently, it has been shown that emitters, such as fluorophores and nitrogen-vacancy centres in diamond, can exhibit a strong non-radiative energy transfer to graphene [2][3][4][5][6] . So far, the energy of the transferred electronic excitations has been considered to be lost within the electron bath of the graphene. Here we demonstrate that the transferred excitations can be read out by detecting corresponding currents with a picosecond time resolution 7,8 . We detect electronically the spin of nitrogen-vacancy centres in diamond and control the non-radiative transfer to graphene by electron spin resonance. Our results open the avenue for incorporating nitrogen-vacancy centres into ultrafast electronic circuits and for harvesting non-radiative transfer processes electronically.With the advancement of nanoscale photonics research it has become increasingly desirable to combine optical systems with electric circuits to create optoelectronic devices that can be miniaturized and integrated into chips. To this end, we can take advantage of the excellent optical and electronic properties of graphene 9 , which include good photodetection capabilities 8,10-15 , efficient energy absorption 3 and strong light-matter interactions at the nanoscale 16,17 . In particular, it has been reported recently that, because of graphene's specific properties, the near-field interaction between light emitters and graphene is greatly enhanced as compared to that of conventional metals 2-6 . This interaction manifests itself, for example, in a 100-fold enhancement of the excited-state decay rate of emitters placed 5 nm away from graphene as compared to the spontaneous emission of the emitter. The physical mechanism behind the interaction is the creation of an electron-hole pair in graphene through non-radiative energy transfer (NRET) from the emitter dipole 18 . The NRET process to graphene has been demonstrated to have an efficiency of nearly 100% when the emitter is less than 10 nm away from the graphene sheet 3 , which makes graphene an ideal material to detect electronically the optical properties of nearby emitters 6 . NRET has been studied extensively for fundamental as well as for biosensing applications. However, a fast energy transfer has not yet been observed because of quenching of the optical signal for short graphene-emitter distances. In contrast, an electronic readout of the NRET enables studies on fast energy processes. Moreover, if the transferred energy can be collected, as we show in this work, new ways for energy harvesting and biosensing can be implemented.We take advantage of the highly efficient NRET process to read out electronically, for the first time, the optical excitation of nitrogen-vacancy (NV) centres in diamond nanocrystals. To this end, we used graphene for the extraction of the excited-state energy of NV centres and converted it into a measurable ...

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confidence: 96%

“…2a). At this position, the electric field is dominated by the built-in potential at the graphene-gold interface 8,14,15,33 . The longlived transient currents (blue-shaded region in Fig.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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Ultrafast electronic readout of diamond nitrogen–vacancy centres coupled to graphene

et al. 2014

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“…Metal nanoparticles are known to dope graphene underneath, which leads to an in-plane electric field in the graphene areas surrounding them 18,20 . It is also known that illumination of such built-in junctions creates long-lived (>1 ps) hot electrons in graphene 24,25 , and these electrons generate a photovoltage 5,26,27 , similar to illumination of semiconducting p-n junctions. The photovoltage V ph in graphene is proportional to its electron temperature, T e .…”

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confidence: 99%

Giant photoeffect in proton transport through graphene membranes

Lozada-Hidalgo

Zhang

et al. 2018

Nature Nanotech

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Graphene has recently been shown to be permeable to thermal protons 1 , the nuclei of hydrogen atoms, which sparked interest in its use as a proton-conducting membrane in relevant technologies 1-4 . However, the influence of light on proton permeation remains unknown. Here we report that proton transport through Pt-nanoparticle-decorated graphene can be enhanced strongly by illuminating it with visible light. Using electrical measurements and mass spectrometry, we find a photoresponsivity of 10 4 A W -1 , which translates into a gain of 10 4 protons per photon with response times in the microsecond range. These characteristics are competitive with those of state-of-the-art photodetectors that are based on electron transport using silicon and novel two-dimensional materials 5-7 . The photo-proton effect can be important for graphene's envisaged use in fuel cells and hydrogen isotope separation. Our observations can also be of interest for other applications such as light-induced water splitting, photocatalysis and novel photodetectors.Recent experiments have established that graphene monolayers are surprisingly transparent to thermal protons, even in the absence of lattice defects 1,2 . The proton transport through graphene was found to be thermally activated 1 with a relatively low energy barrier of about 0.8 eV. Further measurements involving hydrogen's isotope deuterium have shown that this barrier is in fact 0.2 eV higher than the measured activation energy because the initial state of incoming protons is lifted by zero-point oscillations at oxygen bonds within the proton-conducting media used in the experiments 2 . The resulting value of 1.0 eV for the graphene barrier is somewhat lower (by at least 30%) than the values obtained theoretically for ideal graphene 1,[8][9][10] , which triggered a debate about the exact microscopic mechanism behind the proton permeation [8][9][10][11][12] . For example, it was recently suggested that graphene's hydrogenation could be an additional ingredient involved in the process 11 . Independently of fundamentals of the involved mechanisms, the high proton conductivity of graphene membranes combined with their impermeability to other atoms and molecules entices their use for various applications including fuel cell technologies and hydrogen isotope separation 1-4 . For example, it was argued that mass-produced membranes based on chemical-vapor-deposited graphene can dramatically increase efficiency and decrease costs of heavy water production 1,2,4 .In this Letter, we describe an unexpected enhancement of proton transport through catalyticallyactivated 1 graphene under low-intensity illumination. The devices used in this work were made from monocrystalline graphene obtained by mechanical exfoliation. The graphene crystals were suspended

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“…We were able to collect localized electronic band information that is not disturbed by signals originating from the substrate, and hence, compared with conventional optical pump-probe techniques, SPCM can provide a higher signal-to-noise ratio. Only recently, ultrafast pump-probe photocurrent techniques have been demonstrated for studying carrier dynamics in carbon nanotube devices by using a collinear pump and probe beams, focused at the same position 20,21 . In addition, ultrafast phenomena in graphene and GaAs NWs have been investigated by measuring terahertz radiation that results from the ultrafast photocurrent in spatially designed circuit structures 22,23 .…”

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confidence: 99%

Imaging Ultrafast Carrier Transport in Nanoscale Field-Effect Transistors

et al. 2014

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One-dimensional nanoscale devices, such as semiconductor nanowires (NWs) and singlewalled carbon nanotubes (SWNTs), have been intensively investigated because of their potential application of future high-speed electronic, optoelectronic, and sensing devices 1-3 .To overcome current limitations on the speed of contemporary devices, investigation of charge carrier dynamics with an ultrashort time scale is one of the primary steps necessary for developing high-speed devices. In the present study, we visualize ultrafast carrier dynamics in nanoscale devices using a combination of scanning photocurrent microscopy and timeresolved pump-probe techniques. We investigate transit times of carriers that are generated near one metallic electrode and subsequently transported toward the opposite electrode based on drift and diffusion motions. Carrier dynamics have been measured for various working conditions. In particular, the carrier velocities extracted from transit times increase for a larger negative gate bias, because of the increased field strength at the Schottky barrier. *Electronic mail: ahny@ajou.ac.kr 2The transit time of the charge carriers is a crucial factor limiting the high frequency response of nanoscale devices; however, traditional radio-frequency measurements are often limited by the high impedance or the RC constants of the devices [4][5][6][7][8] . Alternatively, optical ultrafast measurement techniques have been widely used to investigate charge carrier dynamics with a time resolution determined by the optical pulse width (down to a few femtoseconds) 9 . Recently, researchers have reported visualizing charge carrier movements in free-standing Si NWs using an ultrafast pump-probe imaging technique 10,11 . The carrier diffusion motions induced by a pump pulse located in the middle of the NWs were visualized; however, these optical measurements are limited for interrogating the carrier dynamics in operating devices because they strongly depend on the non-linear properties of materials and they are frequently obscured by the substrate signals. Consequently, these techniques are not ideal for low-dimensional systems with NWs thinner than the optical spot size (<100 nm) or with SWNTs.Scanning photocurrent microscopy (SPCM) techniques have been introduced as powerful tools for investigating local optoelectronic characteristics, such as metallic contacts, defects, interfaces, and junctions [12][13][14][15][16][17][18][19] . We were able to collect localized electronic band information that is not disturbed by signals originating from the substrate, and hence, compared with conventional optical pump-probe techniques, SPCM can provide a higher signal-to-noise ratio. Only recently, ultrafast pump-probe photocurrent techniques have been demonstrated for studying carrier dynamics in carbon nanotube devices by using a collinear pump and probe beams, focused at the same position 20,21 . In addition, ultrafast phenomena in graphene and GaAs NWs have been investigated by measuring terahertz radiation that results from...

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Ultrafast hot-carrier-dominated photocurrent in graphene

Cited by 403 publications

References 34 publications

Ultrafast electronic readout of diamond nitrogen–vacancy centres coupled to graphene

Ultrafast electronic readout of diamond nitrogen–vacancy centres coupled to graphene

Giant photoeffect in proton transport through graphene membranes

Imaging Ultrafast Carrier Transport in Nanoscale Field-Effect Transistors

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