Graphene-Silicon Schottky Diodes

Chen, Chun-Chung; Aykol, Mehmet; Chang, Chia-Chi; Levi, A. F. J.; Cronin, Stephen B.

doi:10.1021/nl104364c

Cited by 447 publications

(316 citation statements)

References 40 publications

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“…We get Φ B ∼0.46eV and η ∼11. These are in the range of previously reported values (0.41< Φ B <0.47 and 2< η <30) for SLG/Si Schottky diodes [34][35][36][37][38][39]. By fitting the I-V curve in reverse bias we get the SBH dependence on applied reverse voltage and find ∆Φ B up to∼80meV at -10V, Fig.5b.…”

Section: Introductionsupporting

confidence: 82%

“…Graphene/Si Schottky PDs at 1550nm have been demonstrated both in free-space [34] and guided mode configurations [35,36], with R ext up to 10mA/W and 0.37A/W respectively. In these devices, a single layer graphene (SLG) acts as electrode in contact with Si, forming a Schottky junction with rectifying characteristics [37][38][39]. In general, graphene is an attractive material for photonics and optoelectronics [40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

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Vertically Illuminated, Resonant Cavity Enhanced, Graphene–Silicon Schottky Photodetectors

et al. 2017

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We report vertically-illuminated, resonant cavity enhanced, graphene-Si Schottky photodetectors (PDs) operating at 1550nm. These exploit internal photoemission at the graphene-Si interface. To obtain spectral selectivity and enhance responsivity, the PDs are integrated with an optical cavity, resulting in multiple reflections at resonance, and enhanced absorption in graphene. Our devices have wavelength-dependent photoresponse with external (internal) responsivity∼20mA/W (0.25A/W). The spectral-selectivity may be further tuned by varying the cavity resonant wavelength. Our devices pave the way for developing high responsivity hybrid graphene-Si free-space illuminated PDs for free-space optical communications, coherence optical tomography and light-radars.

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Section: Introductionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Vertically Illuminated, Resonant Cavity Enhanced, Graphene–Silicon Schottky Photodetectors

et al. 2017

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“…Recently both graphene/Si [49][50] and graphene/Ge 51 Schottky junctions based photodetectors using planar Si and Ge substrates have been demonstrated. Here we fabricated a SLG/Ge/Si-tip device by transferring CVD graphene layer on fully coherent Ge islands grown on Si-tip substrates.…”

Section: Resultsmentioning

confidence: 99%

Photodetection in Hybrid Single-Layer Graphene/Fully Coherent Germanium Island Nanostructures Selectively Grown on Silicon Nanotip Patterns

Niu

Capellini

Łupina

et al. 2016

ACS Appl. Mater. Interfaces

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Dislocation networks are one of the most principle sources deteriorating the performances of devices based on lattice-mismatched heteroepitaxial systems. We demonstrate here a technique enabling fully coherent Ge islands selectively grown on nano-tip patterned Si (001) substrates. The Si-tip patterned substrate, fabricated by complementary metal-oxidesemiconductor (CMOS) compatible nanotechnology, features ~50 nm wide Si areas emerging from a SiO 2 matrix and arranged in an ordered lattice. Molecular beam epitaxy (MBE) growths result in Ge nano-islands with high selectivity and having homogeneous shape and size. The ~850°C growth temperature required for ensuring selective growth has been shown to lead to the formation of Ge islands of high crystalline quality without extensive Si intermixing (with 91 at.% Ge). Nano-tip patterned wafers result in geometric, kinetic diffusion barrier intermixing hindrance confining the major intermixing to the pedestal region of Ge islands where kinetic diffusion barriers are however high. Theoretical calculations suggest that the thin SiGe layer at the interface plays nevertheless a significant role in realizing our fully coherent Ge nano-islands free from extended defects especially dislocations. Single layer graphene (SLG)/Ge/Si-tip Schottky junctions were fabricated and thanks to the absence of extended defect in Ge islands, they demonstrate high performance photodetection characteristics with responsivity and I on /I off ratio of ~45 mA/W and ~10 3 , respectively.

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“…In a typical scenario T 0 φ, the conductance in the dark state is exponentially suppressed with increasing temperature as G D ≈ G 0 exp(−φ/T 0 ), in agreement with the qualitative behavior observed in Refs. [2][3][4][7][8][9][10]. To give an estimate of the range of conductances achievable in g/X devices, G D in these experiments report G D ∼ 0.1 − several × µS/µm 2 for φ Si ∼ 0.3 eV with T 0 at room temperature.…”

mentioning

confidence: 99%

“…The value of G 0 can be estimated from conductance measured in the dark state, G D , obtained in actual g/X devices at equilibrium T g = T 0 (for example g/Si Schottky junctions in Refs. [7,8]). Indeed, under an infinitesimally small potential bias δV b , we can approximate ∆f in Eq.…”

mentioning

confidence: 99%

Enhanced Thermionic-Dominated Photoresponse in Graphene Schottky Junctions

Rodriguez-Nieva¹,

Dresselhaus²,

Song

2016

Nano Lett.

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Vertical heterostructures of van der Waals materials enable new pathways to tune charge and energy transport characteristics in nanoscale systems. We propose that graphene Schottky junctions can host a special kind of photoresponse which is characterized by strongly coupled heat and charge flows that run vertically out of the graphene plane. This regime can be accessed when vertical energy transport mediated by thermionic emission of hot carriers overwhelms electron-lattice cooling as well as lateral diffusive energy transport. As such, the power pumped into the system is efficiently extracted across the entire graphene active area via thermionic emission of hot carriers into a semiconductor material. Experimental signatures of this regime include a large and tunable internal responsivity R with a non-monotonic temperature dependence. In particular, R peaks at electronic temperatures on the order of the Schottky potential φ and has a large upper limit R ≤ e/φ (e/φ = 10 A/W when φ = 100 meV). Our proposal opens up new approaches for engineering the photoresponse in optically-active graphene heterostructures.Keywords: graphene; hot carriers; Schottky junction; photocurrent Vertical heterostructures comprising layers of van der Waals (vdW) materials have recently emerged as a platform for designer electronic interfaces [1]. Of special interest are heterostructures which feature tunable interlayer transport characteristics, as exemplified by g/X Schottky junctions [2-10]; here 'g' denotes graphene, and X is a semiconductor material, such as Si, MoS 2 or WSe 2 . These junctions are characterized by Schottky barriers φ that span two orders of magnitude φ ≈ 0.01−1 eV and exhibit in situ control through applied bias or by using gate potentials [7][8][9][10][11]. The wide range of φ achievable across the g/X interface, combined with the unique graphene photoresponse mediated by long-lived hot carriers (elevated electronic temperatures, T g , different from those of the lattice, T 0 [12-17]), make graphene Schottky junctions a prime target for accessing novel vertical energy transport regimes [18].Here we show that specially designed graphene Schottky junctions can host an enhanced thermionicdominated photoresponse driven by strongly coupled charge and energy currents. Such photoresponse proceeds, as illustrated in Fig. 1a, via the thermionic emission of graphene hot carriers with energy larger than the Schottky barrier. At steady state, an equal number of cold carriers are injected at the Fermi surface through an ohmic contact, giving a net flow of heat J ⊥ q out of the graphene electronic system balancing the energy pumped into the system. Strikingly, thermionic emission yields strong heat transport running vertically out of the hot electron system, which dominates over more conventional electronic cooling channels, e.g. electron-lattice cooling. Indeed, we find that J ⊥ q can be significant in graphene (see Fig. 1c) when k B T g ≈ φ/2, dominating over acoustic and optical phonon cooling [12,13] in pristine graphene Sch...

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Graphene-Silicon Schottky Diodes

Cited by 447 publications

References 40 publications

Vertically Illuminated, Resonant Cavity Enhanced, Graphene–Silicon Schottky Photodetectors

Vertically Illuminated, Resonant Cavity Enhanced, Graphene–Silicon Schottky Photodetectors

Photodetection in Hybrid Single-Layer Graphene/Fully Coherent Germanium Island Nanostructures Selectively Grown on Silicon Nanotip Patterns

Enhanced Thermionic-Dominated Photoresponse in Graphene Schottky Junctions

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