Prospective Performance of Graphene HEB for Ultrasensitive Detection of Sub-mm Radiation

Karasik, Boris S.; McKitterick, Christopher B.; Prober, D. E.

doi:10.1007/s10909-014-1087-7

Cited by 23 publications

(12 citation statements)

References 31 publications

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“…Because of this extraordinarily high responsivity, the contribution of Johnson-Nyquist (JN) noise to the noise equivalent power is 5 extremely small, notwithstanding the high device resistance. Other sources of noise that are intrinsic to the bolometer and do not depend on the measurement circuit are shot noise (SN) and thermal fluctuations (TF) 10,11 . We estimate the shot noise from the device I DC at the bias point where we measure the response V DC and the noise due to thermal fluctuations using the thermal conductance extracted from the electrical characteristics of each device (see discussion above to extract G TH of a 30-nm dot using the measurements in Fig.…”

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confidence: 99%

Epitaxial graphene quantum dots for high-performance terahertz bolometers

et al. 2016

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2Light absorption in graphene causes a large change in electron temperature, due to low electronic heat capacity and weak electron phonon coupling, 1-3 making it very attractive as a hot-electron bolometer material. Unfortunately, the weak variation of electrical resistance with temperature has substantially limited the responsivity of graphene bolometers. Here we show that quantum dots of epitaxial graphene on SiC exhibit an extraordinarily high variation of resistance with temperature due to quantum confinement, higher than 430 M K -1 at 2.5 K, leading to responsivities for absorbed THz power above 1 × 10 10 V W -1 . This is five orders of magnitude higher than other types of graphene hot electron bolometers. The high responsivity combined with an extremely low noise-equivalent power, about 2 × 10 -16 W/√Hz at 2.5K, place the performance of graphene quantum dot bolometers well above commercial cooled bolometers. Additionally, these quantum dot bolometers have the potential for superior performance for operation above 77K.The electrical resistivity of pristine graphene shows a weak temperature dependence, varying by less than 30% (200% for suspended graphene) from 30 mK to room temperature 4,5 , because of the very weak electron-phonon scattering 6 . A stronger temperature dependence was obtained either by using dual-gated bilayer graphene 1,7 to create a tunable band gap 7 , or by introducing defects to induce strong localization 2 . Both schemes have successfully produced bolometric detection, with responsivities up to 2 × 10 5 V W -1 and temperature coefficient for the resistance as high as 22 kK -1 at 1.5K 1,2 . These devices required the use of multilayer structures adding complexity. In the case of bilayer graphene, top and bottom gates were needed to electrically induce a bandgap. In the case of disordered graphene, a boron nitride layer was used as a tunneling barrier between the graphene and the electrodes to reduce thermal conductance due to diffusion of the electrons to the electrodes. 3Here we demonstrate hot-electron bolometric detection using nano-patterned dots of epitaxial graphene. A bandgap is induced via quantum confinement, without the need of gates, using a simple single-layer structure. We study the THz response of dots with diameter varying from 30 nm to 700 nm, at 0.15 THz and at temperatures from 2.5K to 80K. These devices are extremely sensitive and the responsivity increases by decreasing the dot diameter, with the smaller dots still showing a clear response at liquid nitrogen temperature. Our fabrication process is fully scalable and easily provides multiple devices on the same chip, making it suitable for bolometer arrays. Moreover, its flexibility allows patterning of arrays of dots electrically connected in parallel, to control the device impedance while preserving the strong temperature dependence.We fabricated our dots using e-beam lithography and a process developed by Yang et al., 8 (see Methods). Fig. 1a shows an image of a typical quantum dot and the temperature dependenc...

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confidence: 99%

Epitaxial graphene quantum dots for high-performance terahertz bolometers

et al. 2016

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“…In this paper we treat the issues of measuring single THz photons and of measuring the power of a very weak incident photon flux. Single photon counting with graphene has been treated in recent papers [11][12][13][14][15], and might be employed, but only if graphene had the extremely small thermal conductance below 1 K which has been extrapolated in a previous study [21]. Our recent experiments, and most others described later, find a much larger extrapolated thermal conductance.…”

Section: Device Physicsmentioning

confidence: 86%

Ultrasensitive graphene far-infrared power detectors

McKitterick

Prober

Vora

et al. 2015

J. Phys.: Condens. Matter

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We describe the properties of ultrasensitive graphene photon detectors for use in the far-infrared/terahertz spectral region and present theoretical predictions for their power detection sensitivity. These predictions are based on two graphene contacting schemes with superconducting contacts: contacts with a thin insulating barrier, and direct superconducting contacts. To quantitatively assess these predictions, we perform thermal measurements of graphene at low temperatures and analyse them to extract information on electron-phonon cooling in graphene. These new results for the electron-phonon cooling channel allow reliable prediction of the noise equivalent power (NEP) that can be expected from an optimized graphene detector, using measurement of the Johnson noise emission as the thermometry method. We find that an NEP of 2 × 10(-19) W Hz(-1/2) should be achievable under certain biasing conditions with an ideal device.

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“…Thus the responsivity is . 2 The output noise is a sum of the Johnson noise and the amplifier noise. The power of the Johnson noise is a variance of [18] and can be expressed as follows:…”

Section: Johnson Noise Readout and Nepmentioning

confidence: 99%

“…Noting that an electron temperature increase in the small signal approximation is 2 This definition of the responsivity is a corrected form of (13) in [1].…”

Section: Johnson Noise Readout and Nepmentioning

confidence: 99%

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Normal-Metal Hot-Electron Nanobolometer With Johnson Noise Thermometry Readout

Karasik

McKitterick

Reck

et al. 2014

IEEE Trans. THz Sci. Technol.

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The sensitivity of a THz hot-electron nanobolometer (nano-HEB) made from a normal metal is analyzed. Johnson Noise Thermometry (JNT) is employed as a readout technique. In contrast to its superconducting Transition-Edge Sensor (TES) counterpart, the normal-metal nano-HEB can operate at any cryogenic temperature depending on the required radiation background limited Noise Equivalent Power (NEP). It does not require bias lines; 100s of nano-HEBs can be read by a single low-noise -band amplifier via a filter bank channelizer. The modeling predicts that even with the sensitivity penalty due to the amplifier noise, an -W/Hz can be expected at 50-100 mK in 10-20 nm thin titanium (Ti) normal metal HEBs with niobium (Nb) contacts. This NEP is fairly constant over a range of readout frequencies 10 GHz. Although materials with weaker electron-phonon coupling (bismuth, graphene) do not improve the minimum achievable NEP, they can be considered if a larger than 10 GHz readout bandwidth is required.

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Prospective Performance of Graphene HEB for Ultrasensitive Detection of Sub-mm Radiation

Cited by 23 publications

References 31 publications

Epitaxial graphene quantum dots for high-performance terahertz bolometers

Epitaxial graphene quantum dots for high-performance terahertz bolometers

Ultrasensitive graphene far-infrared power detectors

Normal-Metal Hot-Electron Nanobolometer With Johnson Noise Thermometry Readout

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