Asymmetrically-gated graphene self-switching diodes as negative differential resistance devices

Al-Dirini, Feras; Hossain, Faruque M.; Nirmalathas, Ampalavanapillai; Skafidas, Efstratios

doi:10.1039/c4nr00112e

Cited by 25 publications

(22 citation statements)

References 56 publications

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“…In accordance with the experimentally determined values, the peak to valley current ratios (PVCR) is 63.4 (I v ¼ 63 pA, I p ¼ 4:0 nA) for the Al/Ge/BN/C channel. The PVCR value is comparable to the values reported as 16, 40, and 135 for GaN/AlN RTD [13], symmetrically gated graphene self-switching diodes [14], and for a C/InSe/MgO/ C RTD [15]. The region where the current decreases with increasing forward voltage (0.1-2.30) for the Al/Ge/BN/C channel is called a negative-resistance region and is, generally, used to achieve switching, amplification, oscillation properties.…”

supporting

confidence: 86%

Design and characterization of (Al, C)/p-Ge/p-BN/C isotype resonant electronic devices

Garni

Qasrawi

2015

Phys. Status Solidi A

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In this work, a Ge/BN isotype electronic device that works as a selective microwave bandstop filter is designed and characterized. The interface is designed using a 50‐μm thick p‐type BN on a 0.2‐μm thick p‐type germanium thin film. The modeling of current–voltage characteristics of the Al/Ge/BN/C channel of the device revealed that the current is dominated by thermionic emission and by the tunneling of charged particles through energy barriers. The evaluation of the conduction parameters reflected a resonant circuit with a peak‐to‐valley current ratio of (PVCR) of 63 at a peak (Vp) and valley (Vv) voltages of 1.84 and 2.30 V, respectively. The ac signal analysis of the Al/Ge/BN/C channel that was carried out in the frequency range of 1.0–3.0 GHz displayed a bandstop filter properties with notch frequency (fn) of 2.04 GHz and quality factor (Q) of 102. The replacement of the Al electrode by C through the C/Ge/BN/C channel caused the disappearance of the PVCR and shifted fn and Q to 2.70 GHz and 100, respectively. The features of the Ge/BN device are promising as they indicate the applicability of these sensors in communication technology.

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supporting

confidence: 86%

Design and characterization of (Al, C)/p-Ge/p-BN/C isotype resonant electronic devices

Garni

Qasrawi

2015

Phys. Status Solidi A

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“…6 Simulations have shown the feasibility of achieving rectification in graphene using SSD structures. 7,8 SSD detectors have previously been realized in other materials [9][10][11][12] with the most promising results for GaAs SSDs in which an NEP of 330 pW/Hz 1 =2 at 1.5 THz was observed. 13 In this work, detection with rectifying graphene SSDs at frequencies up to 67 GHz is demonstrated.…”

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confidence: 99%

Graphene self-switching diodes as zero-bias microwave detectors

Westlund

Winters

Ivanov

et al. 2015

Applied Physics Letters

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Self-switching diodes (SSDs) were fabricated on as-grown and hydrogen-intercalated epitaxial graphene on SiC. The SSDs were characterized as zero-bias detectors with on-wafer measurements from 1 to 67 GHz. The lowest noise-equivalent power (NEP) was observed in SSDs on the hydrogen-intercalated sample, where a flat NEP of 2.2 nW/Hz 1 =2 and responsivity of 3.9 V/W were measured across the band. The measured NEP demonstrates the potential of graphene SSDs as zero-bias microwave detectors. Graphene exhibits electronic properties which are relevant for high-frequency applications 1 such as zero-bias detection in passive imaging arrays. 2 Detectors drawing zero bias current offer reduced 1/f-noise compared to biased detectors. Zero-bias detectors are today normally based on heterojunctions or Schottky diodes, reaching noise-equivalent power (NEP) below 20 pW/Hz 1 =2 beyond 100 GHz. 3,4 Zero-bias detection has been demonstrated in graphene field-effect transistors (FETs) with an NEP of 515 pW/Hz 1 =2 at 600 GHz. 5 Self-switching diodes (SSDs) offer a fundamentally different approach to zero-bias detection in which rectification and detection is achieved by a lateral field-effect. 6 Simulations have shown the feasibility of achieving rectification in graphene using SSD structures. 7,8 SSD detectors have previously been realized in other materials 9-12 with the most promising results for GaAs SSDs in which an NEP of 330 pW/Hz 1 =2 at 1.5 THz was observed. 13 In this work, detection with rectifying graphene SSDs at frequencies up to 67 GHz is demonstrated. The SSDs are realized in both as-grown (n-type) and hydrogen-intercalated (p-type) epitaxial graphene on SiC. Figure 1 shows a scanning electron micrograph of a single SSD channel fabricated in epitaxial graphene. The narrow graphene channel behaves as a lateral nanowire transistor. 6 The surrounding flanges act as lateral gates which are directly connected to the drain such that the drain voltage is simultaneously applied to the gates. This has the effect of modulating the carrier density in the nanowire channel generating a nonlinear current-voltage characteristic. 14 The inset shows an SSD design implemented for RF detection with nine nanowire channels acting in parallel to reduce resistance and NEP. 15 The SSDs were fabricated at the end of a 70 lm coplanar transmission line, in order to provide a partial RF match.Graphene was grown on the Si-face of two 20 Â 20 mm 2 nominally on-axis semi-insulating (SI) 4H-SiC substrates in a horizontal hot wall chemical vapor deposition (CVD) reactor. 16 Graphene growth was carried out at 1300 C to 1400 C in vacuum after an initial in-situ surface preparation of the substrates in a hydrogen/silane background. One of the samples was then intercalated in hydrogen at a temperature (pressure) of 800 C (500 mbar) in order to obtain quasi-free standing graphene. SSDs and supplementary test structures were fabricated on the graphene layers with and without H-intercalation. As-grown samples then consisted of a monolayer plus carbon buf...

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“…This suggests that efficient high frequency detection in graphene nanowire diodes (GNDs) is feasible to similar effect. [9][10][11] As monolayer and bilayer graphene are semi-metallic materials exhibiting ambipolar transport, the nonlinearity which facilitates detection is of a different character than that seen in semiconducting nanowire diodes. Nanowire structures are formed by etching narrow trenches into an electrically isolated graphene mesa.…”

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confidence: 99%

High frequency electromagnetic detection by nonlinear conduction modulation in graphene nanowire diodes

Winters

Thorsell

Strupiński

et al. 2015

Applied Physics Letters

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We present graphene nanowires implemented as dispersion free self switched microwave diode detectors. The microwave properties of the detectors are investigated using vector corrected large signal measurements in order to determine the detector responsivity and noise equivalent power (NEP) as a function of frequency, input power, and device geometry. We identify two distinct conductance nonlinearities which generate detector responsivity: an edge effect nonlinearity near zero bias due to lateral gating of the nanowire structures, and a velocity saturation nonlinearity which generates current compression at high power levels. The scaling study shows that detector responsivity obeys an exponential scaling law with respect to nanowire width, and a peak responsivity (NEP) of 250 V/W (50 pW/ ffiffiffiffiffiffi Hz p ) is observed in detectors of the smallest width. The results are promising as the devices exhibit responsivities which are comparable to state of the art self switched detectors in semiconductor technologies. V C 2015 AIP Publishing LLC.

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Asymmetrically-gated graphene self-switching diodes as negative differential resistance devices

Cited by 25 publications

References 56 publications

Design and characterization of (Al, C)/p-Ge/p-BN/C isotype resonant electronic devices

Design and characterization of (Al, C)/p-Ge/p-BN/C isotype resonant electronic devices

Graphene self-switching diodes as zero-bias microwave detectors

High frequency electromagnetic detection by nonlinear conduction modulation in graphene nanowire diodes

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