Disordered multiwalled carbon nanotube mat for light spot position detecting

Sun, Jia‐Lin; Xu, Jia; Zhu, Jia‐Lin; Li, Baolei

doi:10.1007/s00339-008-4398-1

Cited by 11 publications

(13 citation statements)

References 32 publications

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“…The data in Fig. 1(a) reproduce the main characteristics previously reported for SWNT films [6,20,21], multi-walled carbon nanotube (MWNT) films [22,25], and reduced graphene oxide sheets [23]. That is, the photoresponse (here both PV and PC) is significantly enhanced at the nanotubes/electrode interfaces and reverses sign as the laser crosses the center of the gap between the electrodes.…”

Section: Methodssupporting

confidence: 74%

“…Thermoelectric contributions have also been identified recently in the transport properties of graphene devices [24]. In another report, a slow contribution in the photoresponse of multi-walled carbon nanotube films was attributed to a thermal effect, named a heterodimension effect [25], which is similar to PTE. The importance of PTE has yet to be assessed for the case of SWNT films deposited on substrates that dissipate effectively the heat induced by the laser excitation.…”

Section: Introductionmentioning

confidence: 96%

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Photothermoelectric effects in single-walled carbon nanotube films: Reinterpreting scanning photocurrent experiments

2011

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We revisit the mechanism leading to the photoresponse of locally illuminated single-walled carbon nanotube (SWNT) films deposited on substrates. Our study examines the impact of multiple device parameters and provides many evidences that the position-dependent photocurrent is dominated by photothermoelectric effects. The photoresponse arises from the temperature variations at the metal-nanotube film interfaces, where mismatches of the Seebeck coefficients are measured. Our work also stresses the impact of the substrates, electrode materials and post-thermal treatments on the amplitude and dynamics of the photoresponse. The knowledge gained should guide the future development of photothermoelectric devices and detectors based on SWNTs.

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Section: Methodssupporting

confidence: 74%

Section: Introductionmentioning

confidence: 96%

Photothermoelectric effects in single-walled carbon nanotube films: Reinterpreting scanning photocurrent experiments

2011

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“…Carbon nanotubes (CNTs) are considered to be promising building blocks for nanoelectronic and optical devices due to their special geometry, high electrical conductivity, and exceptional mechanical and optical properties [1-2]. In particular, photoresponse studies of pure CNT films and CNT/Polymer composites have attracted tremendous attention because of their promising applications for bolometer, position sensor and photovoltaic devices [3][4][5][6]. Itkis et al found that in single walled carbon nanotube (SWNT) film, the photoresponse was due to a bolometric effect, a change in conductivity due to heating of the SWNT network [3], while Levitsky et al showed that in SWNT film, molecular photodesorption to be responsible for change in conductivity upon near IR illumination [7].…”

Section: Introductionmentioning

confidence: 99%

Diffusion mediated photoconduction in multiwalled carbon nanotube films

Sarker¹,

Arif²,

Stokes³

et al. 2009

Journal of Applied Physics

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We investigated the mechanism for photoconduction in multi-walled carbon nanotube (MWNT) film of various electrode separations upon near infrared illumination. In addition to observing strong dependence of photocurrent on the position of the laser spot, we found that the time constant of the dynamic photoresponse is slow and increases with increasing electrode separations. The photoconduction mechanism can be explained by the Schottky barrier modulation at the metal-nanotube film interface and charge carrier diffusion through percolating MWNT networks.

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“…It can be seen from this figure that time response for photocurrent is very slow. We found that our data can be well described using the equation  are two characteristic time constants [23]. We would like to note that, we also attempted to fit our data with a single exponential,  could be related to the diffusion of charge carriers through the interpenetrating NW network where carrier needs to tunnel from one NW to the next through the NW junction.…”

Section: Methodsmentioning

confidence: 93%

The electronic transport properties of ternary Cd_1−xZn_xS nanowire networks

et al. 2009

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We present electronic transport characteristics of ternary alloy Cd 1-x Zn x S nanowire networks in the dark and under white light illumination. Compared to the negligible dark current, we observed a photocurrent enhancement up to 4 orders of magnitude at intensity of 460 mW/cm 2 . The time constant of the dynamic photoresponse is ~5 sec. The current -voltage characteristics at different intensities show Ohmic behavior at low bias and space charge limited conduction (SCLC) at higher bias voltages. The SCLC behavior and slow time response indicate that the charge transport is dominated by tunneling at the percolating inter-nanowire junctions.(Some figures in this article are in color only in the electronic version) Introduction:Chemically synthesized semiconductor nanocrystals have attracted tremendous interest because of the ability to tune their band gap through variation of their sizes and shapes. These nanocrystalline materials, specially that work in the visible range, have great potential for applications in optoelectronic devices such as solar cells, light emitting diodes, lasers, waveguides and photodetectors [1][2][3][4][5]. In addition, their ease of processibility from solution is of great advantage as they can cover large areas at low cost and are compatible with flexible substrates. Many studies have been done on semiconductor quantum dots [4][5][6][7][8] and quantum dot polymer composites [9][10][11]. However, it is believed that materials that are one dimensional (nanorods, nanowires) can provide added benefit as they make a percolating pathway for charge transport rather easily compared to zero dimensional quantum dots. There have been several reports on the optoelectronic studies of binary nanowires (NWs) [1][2][3][12][13][14][15]. For example, Huynh et al used CdSe nanorods for making organic-inorganic hybrid solar cells [2]. Kind et al used ZnO NWs for ultraviolet photodetectors and optical switches [3]. Nonetheless, tuning the bandgap by varying the diameter and aspect ratio of one-dimensional NWs is extremely challenging. An alternative route of tuning the bandgaps of NWs is to engineer the relative composition of the materials to fabricate ternary alloy NWs. Despite the obvious advantage of ternary nanowires over binary NWs, there are only a few reports on the growth and optical properties of several ternary NW systems [16][17][18][19], and no reports on the optoelectronic investigation of any ternary NWs. Study of charge transport and photoresponse properties of ternary NW network film is important in order to determine whether this material could be useful for optoelectronic applications.In this paper, we report on the first optoelectronic transport characteristics of ternary alloy Cd 1-x Zn x S NW network devices. The NW films were prepared by drop-casting the NWs from solution on inter-digitated gold source and drain electrodes fabricated on Si/SiO 2 substrate.

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Disordered multiwalled carbon nanotube mat for light spot position detecting

Cited by 11 publications

References 32 publications

Photothermoelectric effects in single-walled carbon nanotube films: Reinterpreting scanning photocurrent experiments

Photothermoelectric effects in single-walled carbon nanotube films: Reinterpreting scanning photocurrent experiments

Diffusion mediated photoconduction in multiwalled carbon nanotube films

The electronic transport properties of ternary Cd_1−xZn_xS nanowire networks

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Disordered multiwalled carbon nanotube mat for light spot position detecting

Cited by 11 publications

References 32 publications

Photothermoelectric effects in single-walled carbon nanotube films: Reinterpreting scanning photocurrent experiments

Photothermoelectric effects in single-walled carbon nanotube films: Reinterpreting scanning photocurrent experiments

Diffusion mediated photoconduction in multiwalled carbon nanotube films

The electronic transport properties of ternary Cd1−xZnxS nanowire networks

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The electronic transport properties of ternary Cd_1−xZn_xS nanowire networks