Inhomogeneity in barrier height at graphene/Si (GaAs) Schottky junctions

Tomer, Dushyant; Rajput, Swati; Hudy, Lawrence; Li, C. H.; Li, L.

doi:10.1088/0957-4484/26/21/215702

Cited by 42 publications

(33 citation statements)

References 47 publications

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“…of ) with forward bias, meaning that the application of a forward bias homogenize the barrier fluctuations. The value of ~74 at zero bias is in agreement or below what has been reported for planar Gr/semiconductor heterojunctions 44,46,49 . This lead to the remarkable result that the tip-geometry and the transfer process do not introduce extra-inhomogeneity.…”

Section: Fig 3csupporting

confidence: 89%

Tunable Schottky barrier and high responsivity in graphene/Si-nanotip optoelectronic device

et al. 2016

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We demonstrate tunable Schottky barrier height and record photo-responsivity in a new-concept device made of a single-layer CVD graphene transferred onto a matrix of nanotips patterned on ntype Si wafer. The original layout, where nano-sized graphene/Si heterojunctions alternate to graphene areas exposed to the electric field of the Si substrate, which acts both as diode cathode and transistor gate, results in a two-terminal barristor with single-bias control of the Schottky barrier. The nanotip patterning favors light absorption, and the enhancement of the electric field at the tip apex improves photo-charge separation and enables internal gain by impact ionization. 2These features render the device a photodetector with responsivity (3 / for white LED light at 3 2 ⁄ intensity) almost an order of magnitude higher than commercial photodiodes. We extensively characterize the voltage and the temperature dependence of the device parameters and prove that the multi-junction approach does not add extra-inhomogeneity to the Schottky barrier height distribution.This work represents a significant advance in the realization of graphene/Si Schottky devices for optoelectronic applications.

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Section: Fig 3csupporting

confidence: 89%

Tunable Schottky barrier and high responsivity in graphene/Si-nanotip optoelectronic device

et al. 2016

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“…Recent work has further indicated that the nonideal behavior of the temperature dependent barrier height and ideality factor greater than one can be attributed to spatial inhomogeneities commonly observed at the junction interface 16,17 . A modified TE model assuming a Gaussian distribution of the barrier height offers a better account of carrier transport in these graphene/semiconductor Schottky junctions 16,17 . For near ideal Gr/Si junction, Landauer transport mechanism is suggested 18 .…”

mentioning

confidence: 99%

“…Details of device fabrication and forward-bias characteristics of these Schottky diodes can be found elsewhere 16,17 . Here, we present studies of the temperature-and electric-field dependence of the junction current under reverse-bias, where we find that while carrier transport in reverse-biased Gr/SiC Schottky junctions follows the Poole-Frenkel mechanism, it deviates 3 from both the Poole-Frankel and Schottky mechanisms in Gr/Si and Gr/GaAs junctions, particularly for low temperatures and electric fields.…”

mentioning

confidence: 99%

“…1(a) for Gr/GaAs at 310 K 16,17 . Under the reverse-bias, however, the current rises with increasing bias voltage, as better seen in the semi-logarithmic plots for Gr/GaAs and Si-face SiC diodes between 250 and…”

mentioning

confidence: 99%

“…Here E is the applied electric field, calculated by = √ for GaAs, and Si, respectively 23 , and the mean SBH values of 1.14 and 0.76 eV are taken for Gr/Si and Gr/GaAs Schottky junctions 17 . For Gr/GaAs (Fig.…”

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confidence: 99%

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Carrier transport in reverse-biased graphene/semiconductor Schottky junctions

Tomer

Rajput

Hudy

et al. 2015

Applied Physics Letters

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Reverse-biased graphene (Gr)/semiconductor Schottky diodes exhibit much enhanced sensitivity for gas sensing. However, carrier transport across the junctions is not fully understood yet. Here, Gr/SiC, Gr/GaAs and Gr/Si Schottky junctions under reverse-bias are investigated by temperature-dependent current-voltage measurements. A reduction in barrier height with increasing reverse-bias is observed for all junctions, suggesting electric-field enhanced thermionic emission. Further analysis of the field dependence of the reverse current reveals that while carrier transport in Gr/SiC Schottky junctions follows the Poole-Frenkel mechanism, it deviates from both the Poole-Frankel and Schottky mechanisms in Gr/Si and Gr/GaAs junctions, particularly for low temperatures and fields.

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High‐Barrier‐Height Ti₃C₂T_x/Si Microstructure Schottky Junction‐Based Self‐Powered Photodetectors for Photoplethysmographic Monitoring

Song

et al. 2022

Adv Materials Technologies

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process technology and the potential for large-scale integration of photodetector networks with readout circuits. [3,4] The device performance of Si-based SBD photodetectors is fundamentally determined by the Schottky barrier height (Ф B ) between the metallic electrode and Si. A high Ф B is much desired for self-powered SBD photodetectors, because the large built-in electric field arising from the high Ф B could effectively enhance the separation and transportation of photo-generated carriers. According to the Schottky-Mott model, [5] the Ф B predominantly dependent on the metal function as well as the interface quality of the metal/semiconductor contact. Although a Ф B value up to 0.9 eV was achieved for these Si-based SBDs, they encounter similar challenges in terms of severe interface metal diffusion and low light transparency.Recently, a new class of 2D transition metal carbides and nitrides, called MXenes, [6] has spurred great research interest as promising building blocks for optoelectronic device applications. [7][8][9][10][11][12] Owing to the high conductivity (e.g., >10 4 S cm −1 for Ti 3 C 2 T x ), large specific area, and high transmittance, 2D MXene nanosheets have been widely used as transparent electrodes to construct MXene-related photodetectors through solution-processable approaches. [13,14] More importantly, the MXenes possess an adjustable work function in a wide range from 1.6 to 5.8 eV, depending on the various surface functional A high Schottky barrier height (Φ B ) is one of the essential prerequisites for achieving high-performance self-powered Schottky-barrier diode (SBD)based photodetector. The Φ B value is predominantly determined by the metal function and interface quality of the metal/semiconductor contact. 2D MXenes with adjustable work functions and dangling bond-free properties are promising building blocks for constructing self-powered SBD with high Φ B . Herein, a novel Ti 3 C 2 T x MXene/Si hexagonal microhole array (SiHMA) van der Waals SBD is developed for the first time via a feasible solution process. Significantly, the device possesses a large Φ B up to ≈1.07 eV, which is among the highest for the Si-based SBD. In consequence, the Ti 3 C 2 T x /SiHMA SBD yields a large responsivity up to 302 mA W −1 and detectivity as high as 5.4 × 10 13 Jones in a self-powered model, surpassing the performance of most 2D material/Si photodiodes reported to date. Furthermore, it is demonstrated that featured and reliable fingertip photoplethysmogram (PPG) signals can be detected using the self-powered SBD, enabling us to further accurately extract the heart rate (HR), and blood pressures (BP) using the PPG-only method. This work paves the way for the construction of high-performance MXenesbased self-powered SBDs for health monitoring.

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Inhomogeneity in barrier height at graphene/Si (GaAs) Schottky junctions

Cited by 42 publications

References 47 publications

Tunable Schottky barrier and high responsivity in graphene/Si-nanotip optoelectronic device

Tunable Schottky barrier and high responsivity in graphene/Si-nanotip optoelectronic device

Carrier transport in reverse-biased graphene/semiconductor Schottky junctions

High‐Barrier‐Height Ti₃C₂T_x/Si Microstructure Schottky Junction‐Based Self‐Powered Photodetectors for Photoplethysmographic Monitoring

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Inhomogeneity in barrier height at graphene/Si (GaAs) Schottky junctions

Cited by 42 publications

References 47 publications

Tunable Schottky barrier and high responsivity in graphene/Si-nanotip optoelectronic device

Tunable Schottky barrier and high responsivity in graphene/Si-nanotip optoelectronic device

Carrier transport in reverse-biased graphene/semiconductor Schottky junctions

High‐Barrier‐Height Ti3C2Tx/Si Microstructure Schottky Junction‐Based Self‐Powered Photodetectors for Photoplethysmographic Monitoring

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High‐Barrier‐Height Ti₃C₂T_x/Si Microstructure Schottky Junction‐Based Self‐Powered Photodetectors for Photoplethysmographic Monitoring