1 jean-françois millithaler a monte carlo investigation of plasmonic noise in nanometric n-in 0.53...

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Jean-François Millithaler

A Monte Carlo investigation of plasmonic noise innanometric n-In0.53Ga0.47As channels

Italian team :Italian team : J.-F. MillithalerJ.-F. Millithaler, L. Reggiani, L. ReggianiUniversita degli studi del SalentoUniversita degli studi del Salento

French team :French team : J. Pousset, L. Varani, C.Palermo, W. Knap J. Pousset, L. Varani, C.Palermo, W. KnapUniversité Montpellier IIUniversité Montpellier II

Spanish team :Spanish team : J. Mateos, T. Gonzalez, S. Perez, D. Pardo J. Mateos, T. Gonzalez, S. Perez, D. PardoUniversidad de SalamancaUniversidad de Salamanca

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OutlineOutline

MotivationMotivation

Simulations : Analytical and Monte CarloSimulations : Analytical and Monte Carlo

ResultsResultsGeneral features of bulkGeneral features of bulk

Ohmic regimeOhmic regime

Balistic regimeBalistic regime

Saturation regimeSaturation regime

Conclusion and open problemsConclusion and open problems

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OutlineOutline








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TeraHertz RadiationTeraHertz Radiation

Situated between 0.3 and 30 THz, 10Situated between 0.3 and 30 THz, 10-3-3 and 10 and 10-5-5 m mEnergy between 1 meV et 100 meVEnergy between 1 meV et 100 meVInteresting physicals propertiesInteresting physicals properties

absorption by water, oscillations of molecules (organic, inorganic, absorption by water, oscillations of molecules (organic, inorganic, biological), non-ionising, etc.biological), non-ionising, etc.

Strong issue for many domainsStrong issue for many domains : :Telecommunications, high-resolution spectroscopy, imaging, Telecommunications, high-resolution spectroscopy, imaging, security, etc.security, etc.


TeraHertzTeraHertz

Applications require low cost, integrated, tunable THz source @room Applications require low cost, integrated, tunable THz source @room temperaturetemperature

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Potential electronic emitter and detectorPotential electronic emitter and detector

HEMT HEMT (High Electron Mobility Transistor)(High Electron Mobility Transistor)

High frequency instabilitiesHigh frequency instabilities

2D Electron gas (plasma) in the 2D Electron gas (plasma) in the channelchannel

Study of THz generation mechanismStudy of THz generation mechanism

TeraHertzTeraHertzInfraredInfrared Micro-waveMicro-wave


OpticOptic ElectronicElectronic

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OutlineOutline


Simulations : Analytical and Monte Carlo Simulations : Analytical and Monte Carlo






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Analytical modelAnalytical model

Bulk = 3D electron gasBulk = 3D electron gas

2D electron gas2D electron gas

3D plasma frequency3D plasma frequency

2D plasma frequency2D plasma frequency

SimulationsSimulations

3D to 2D ?3D to 2D ?

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Monte Carlo ModelMonte Carlo Model

Length (Length (LL) : 10) : 10-2-2 to 10 µm to 10 µm

Width (Width (WW) : 1 to 100 nm) : 1 to 100 nm

Concentration : 10Concentration : 101515 to 10 to 101818 cmcm-3-3

Applied VoltageApplied Voltage

SimulationsSimulations

Study of voltage fluctuations :Study of voltage fluctuations :

Monte Carlo SimulatorMonte Carlo Simulator

Resolution of Poisson Resolution of Poisson equationequation

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OutlineOutline








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Bulk characteristicsBulk characteristics

10101717 cm cm-3-3 : v = 2.3 10 : v = 2.3 1055 m/s at E = m/s at E = 4.2 kV/cm4.2 kV/cm

10101818 cm cm-3-3 : v = 1.9 10 : v = 1.9 1055 m/s at E = m/s at E = 4.7 kV/cm4.7 kV/cm

ResultsResults

Typical current-voltage Typical current-voltage characteristiccharacteristic

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Monte Carlo vs RLC modelMonte Carlo vs RLC model

L = 0.1 µmL = 0.1 µm

W = 100 nmW = 100 nm

nn3D3D = 10 = 101717 cm cm-3-3

ResultsResults

RLC model :RLC model :

slopesslopes

Resonant frequencyResonant frequency

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Asymptotic decay like fAsymptotic decay like f-2-2

Momemtum frequency fMomemtum frequency fmm

Fitting with Gaussian Fitting with Gaussian functionfunction

ResultsResults

101015 15 cmcm-3-3 101017 17 cmcm-3-3

101018 18 cmcm-3-3

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OutlineOutline








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nn3D3D=10=101616 cm cm-3-3, , nn3D3D=10=101717 cm cm-3-3, , nn3D3D=10=101818 cm cm-3-3

Frequency vs LengthFrequency vs Length

ResultsResults

3D (W = 100 nm)3D (W = 100 nm) 2D (W = 1 nm)2D (W = 1 nm)

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Influence of the widthInfluence of the width

2D agreement for W=1 & 2 nm2D agreement for W=1 & 2 nm

2D for W > 5 nm and 0.1 < L < 2.0 µm2D for W > 5 nm and 0.1 < L < 2.0 µm

3D for W > 5 nm and L > 2.0 µm3D for W > 5 nm and L > 2.0 µm

ResultsResults

W = 100 W = 100 nmnm

W = 1 nmW = 1 nm

W = 2 nmW = 2 nm

W = 5 nmW = 5 nm

W = 10 nmW = 10 nm

Increase of the plasma peak when Increase of the plasma peak when

L decreasesL decreases

Peak independent of WPeak independent of W

nn3D3D = 10 = 101717 cm cm-3-3

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2D-3D Cross-over2D-3D Cross-over

Same behaviour for different concentrationsSame behaviour for different concentrations

Cross-over for width around 10 nmCross-over for width around 10 nm

ResultsResults

3D behaviour3D behaviour

2D 2D behaviourbehaviour

Value of frequency peak vs Width for L = 0.1 ( ) and 1.0 µm ( )Value of frequency peak vs Width for L = 0.1 ( ) and 1.0 µm ( )

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OutlineOutline








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ResistivityResistivity

Balistic : independant of Balistic : independant of lengthlength

Diffusive : proportional to Diffusive : proportional to lengthlength

ResultsResults

Good agreement with Butcher equationGood agreement with Butcher equation

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Amplitude of the peakAmplitude of the peak

ResultsResults

10101818 cm cm-3-3, W = 1nm, W = 1nm

Balistic regime conclusion :Balistic regime conclusion :

Independent of WIndependent of W

Peak disappears at L = 1 nmPeak disappears at L = 1 nm

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OutlineOutline








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From plasma to Gunn (1/2)From plasma to Gunn (1/2)

nn3D3D = 10 = 101717 cm cm-3-3 L = 0.5 µm W = 1 nm L = 0.5 µm W = 1 nm

ResultsResults

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From plasma to Gunn (2/2)From plasma to Gunn (2/2)

ResultsResults

nn3D3D = 10 = 101818 cm cm-3-3 L = 0.5 µm W = 1 nm L = 0.5 µm W = 1 nm

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ConclusionConclusion

EquilibriumEquilibrium

W > 100 nm : 3D PlasmaW > 100 nm : 3D Plasma

W < 100 nm : cross-over 3D-2D Plasma around 10 nmW < 100 nm : cross-over 3D-2D Plasma around 10 nm

Ohmic Ohmic

Balistic -> L < 100 nm Balistic -> L < 100 nm

Plasma frequency independent of WPlasma frequency independent of W

Plasma peak suppressed at shorter LPlasma peak suppressed at shorter L

Saturation Saturation

-> cross-over Plasma to Gunn frequency-> cross-over Plasma to Gunn frequency

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Open pointsOpen points

For W = 5 and 10 nm -> 2D and 3D behaviour For W = 5 and 10 nm -> 2D and 3D behaviour depending of the length.depending of the length.

In the balistic regime, when L < 100 nm, the In the balistic regime, when L < 100 nm, the simulations exhibit a frequency peak which is simulations exhibit a frequency peak which is unexpectedly independent of W, and whose amplitude unexpectedly independent of W, and whose amplitude decreases significantly at lowering the channel length.decreases significantly at lowering the channel length.

Electrostatic screening for a 2D electron gas remains Electrostatic screening for a 2D electron gas remains in general an unsolved problem.in general an unsolved problem.

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Thank you for your attentionThank you for your attention

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Main conclusionMain conclusion

Independent of WIndependent of W

Peak disappear at L = 1 nmPeak disappear at L = 1 nm

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Ohmic regime conclusionOhmic regime conclusion

Cross-over between 2D and 3DCross-over between 2D and 3D

Cross-over for width around 10 nm, independently of Cross-over for width around 10 nm, independently of the concentrationthe concentration

1 jean-françois millithaler a monte carlo investigation of plasmonic noise in nanometric n-in 0.53...

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