A low Schottky barrier height and transport mechanism in gold–graphene–silicon (001) heterojunctions

Courtin, Jules; Gall, Sylvain Le; Chrétien, Pascal; Moréac, Alain; Delhaye, Gabriel; Lépine, Bruno; Tricot, Sylvain; Turban, Pascal; Schieffer, Philippe; Breton, Jean-Christophe Le

doi:10.1039/c9na00393b

Cited by 10 publications

(15 citation statements)

References 42 publications

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“…The results are also in agreement with those of Zhong et al [ 28 ], who found a decrease in

when a graphene layer was inserted into a GaN SBD. According to Courtin et al [ 22 ], a similar variation for a graphene–silicon interface was obtained. Inaba et al [ 29 ] also found a very low

at a CNT–SiC interface.…”

Section: Resultssupporting

confidence: 56%

“…As the graphene workfunction increased from 4 to 4.8 eV, the output current was affected ( Figure 9 ) and

increased from 0.320 eV to 0.545 eV as presented in Figure 10 . This increase in

can be interpreted according to the simple Schottky–Mott model as the difference between the workfunction of graphene (

) and the affinity of β-

(

) [ 22 ]:

…”

Section: Resultsmentioning

confidence: 99%

“…The external generation rate

is neglected since the forward bias is within low injection levels [ 2 ]. The tunneling mechanism through graphene, which has an important effect [ 22 , 23 ], has to be considered together with thermionic emissions, Shockley–Read–Hall and Auger recombination, Klassen’s concentration and mobility-dependent temperature, and a reduction in the image force in the simulation. For the graphene layer’s simulation, we considered this layer to be an ultra-thin (0.34 nm thickness) semiconductor with high mobilities, a low tunneling mass, and a low bandgap (0–0.45 eV).…”

Section: Simulation Methodologymentioning

confidence: 99%

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Control of Ni/β-Ga2O3 Vertical Schottky Diode Output Parameters at Forward Bias by Insertion of a Graphene Layer

2022

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Controlling the Schottky barrier height (ϕB) and other parameters of Schottky barrier diodes (SBD) is critical for many applications. In this work, the effect of inserting a graphene interfacial monolayer between a Ni Schottky metal and a β-Ga2O3 semiconductor was investigated using numerical simulation. We confirmed that the simulation-based on Ni workfunction, interfacial trap concentration, and surface electron affinity was well-matched with the actual device characterization. Insertion of the graphene layer achieved a remarkable decrease in the barrier height (ϕB), from 1.32 to 0.43 eV, and in the series resistance (RS), from 60.3 to 2.90 mΩ.cm2. However, the saturation current (JS) increased from 1.26×10−11 to 8.3×10−7(A/cm2). The effects of a graphene bandgap and workfunction were studied. With an increase in the graphene workfunction and bandgap, the Schottky barrier height and series resistance increased and the saturation current decreased. This behavior was related to the tunneling rate variations in the graphene layer. Therefore, control of Schottky barrier diode output parameters was achieved by monitoring the tunneling rate in the graphene layer (through the control of the bandgap) and by controlling the Schottky barrier height according to the Schottky–Mott role (through the control of the workfunction). Furthermore, a zero-bandgap and low-workfunction graphene layer behaves as an ohmic contact, which is in agreement with published results.

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“…The results are also in agreement with those of Zhong et al [ 28 ], who found a decrease in

when a graphene layer was inserted into a GaN SBD. According to Courtin et al [ 22 ], a similar variation for a graphene–silicon interface was obtained. Inaba et al [ 29 ] also found a very low

at a CNT–SiC interface.…”

Section: Resultssupporting

confidence: 56%

“…As the graphene workfunction increased from 4 to 4.8 eV, the output current was affected ( Figure 9 ) and

increased from 0.320 eV to 0.545 eV as presented in Figure 10 . This increase in

can be interpreted according to the simple Schottky–Mott model as the difference between the workfunction of graphene (

) and the affinity of β-

(

) [ 22 ]:

…”

Section: Resultsmentioning

confidence: 99%

“…The external generation rate

Section: Simulation Methodologymentioning

confidence: 99%

See 1 more Smart Citation

Control of Ni/β-Ga2O3 Vertical Schottky Diode Output Parameters at Forward Bias by Insertion of a Graphene Layer

2022

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“…In contrast, the role played by the MIGS is much less clear when replacing the metal with a graphene layer. More specifically the Fermi level was found unpinned at the graphene/passivated-silicon interface [18,[28][29][30] indicating that the MIGS and the interface defect states density must be low (typically below 10 12 states/eV/cm 2 ).…”

Section: Introductionmentioning

confidence: 99%

Origin of weak Fermi level pinning at the graphene/silicon interface

et al. 2020

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The mechanisms governing the formation of Schottky barriers at graphene/hydrogenpassivated silicon interfaces where the graphene plays the role of a two-dimensional (2D) metal electrode have been investigated by means of x-ray photoemission spectroscopy and density functional theory (DFT) calculations. To control the graphene work function without altering neither the structure nor the band dispersion of graphene we used a method that consists in depositing small amounts of gold forming clusters on the graphene/hydrogenpassivated silicon system under ultra-high vacuum environment. We observe from experimental measurements that the Fermi level is mainly free from pinning at the graphene/hydrogen-silicon interface whereas for a semi-infinite metal on silicon the Fermi level is almost fully pinned. This alleviation of the Fermi level pinning observed with the graphene layer is explained by DFT calculations showing that the graphene and the semiconductor are decoupled and that the metal-induced gap states (MIGS) density at the silicon midgap at the interface is very low (< 5 × 10 10 states/eV/cm 2 ). The important conclusion that stems from the DFT results analysis is that the low MIGS density at the semiconductor midgap is related to the 2D nature of the graphene layer. More precisely, the MIGS density is low owing to the lack of propagating states perpendicular to the graphene layer. This finding brings precious information to understand the mechanisms that govern the

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“…Many different new functionalities were observed such as bias-controlled Schottky barrier height [2,3] (SBH), photodetectors [4][5][6][7][8][9] or solar cells [10][11][12]. When covered with a metal, Metal/G/Si can be used as an efficient spin injector [13,14] or a low-resistance contact [15,16]. The reduction of the Si SBH is made possible by simultaneous etching of the silicon oxide and hydrogen passivation of the surface with graphene already on top [17].…”

Section: Introductionmentioning

confidence: 99%

Reduction of Schottky Barrier Height at Graphene/Germanium Interface with Surface Passivation

et al. 2019

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Fermi level pinning at metal/semiconductor interfaces forbids a total control over the Schottky barrier height. 2D materials may be an interesting route to circumvent this problem. As they weakly interact with their substrate through Van der Waals forces, deposition of 2D materials avoids the formation of the large density of state at the semiconductor interface often responsible for Fermi level pinning. Here, we demonstrate the possibility to alleviate Fermi-level pinning and reduce the Schottky barrier height by the association of surface passivation of germanium with the deposition of 2D graphene.

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A low Schottky barrier height and transport mechanism in gold–graphene–silicon (001) heterojunctions

Abstract: ResiScope mapping showing the strong reduction of resistance induced by a graphene sheet inserted between silicon and gold.

Cited by 10 publications

References 42 publications

Control of Ni/β-Ga2O3 Vertical Schottky Diode Output Parameters at Forward Bias by Insertion of a Graphene Layer

Control of Ni/β-Ga2O3 Vertical Schottky Diode Output Parameters at Forward Bias by Insertion of a Graphene Layer

Origin of weak Fermi level pinning at the graphene/silicon interface

Reduction of Schottky Barrier Height at Graphene/Germanium Interface with Surface Passivation

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