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Physical Phenomena for TeraHertz Electronic Devices. Jérémi TORRES Institute of Electronics of the South University Montpellier France. Outline. TeraHertz : Generalities Physical phenomena Plasma-waves Optical-phonon resonance Conclusions. The High-Frequency Investigation Group.

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physical phenomena for terahertz electronic devices
Physical Phenomenafor TeraHertzElectronic Devices
  • Jérémi TORRES
  • Institute of Electronics of the South
  • University Montpellier
  • France
outline
Outline
  • TeraHertz : Generalities
  • Physical phenomena
      • Plasma-waves
      • Optical-phonon resonance
      • Conclusions
the high frequency investigation group
The High-Frequency Investigation Group

Microwaves

Antennas/Radars

EM Compatibility

RFID

Theory

Monte Carlo

Hydrodynamic

Drift-Diffusion

Experiments

Photoexcitation

THz devices

Near-field

EM cartography

slide4

The TeraHertz “gap”

f = 1012 Hz, 300 GHz - 10 THz, λ = 1 mm - 30 μm

Electronics

Photonics

Low cost

Compact

Room temperature

Continuous-wave

Tunable

Integration

power vs frequency
Power vs frequency

Proc. of IEEE 23, 10 (2005)

optical thz devices
Optical THz Devices
  • Direct
    • Gas laser
    • Free electron laser
    • p-Ge laser
    • Quantum cascade laser

Indirect

  • Laser Beating + photoconductor
  • Femtosecond laser + nonlinear cristal

Difficulties:

complexity, cost, magnetic field, maintenance, temperature

electronic thz devices
Electronic THz Devices
  • Direct
    • Gunn, RTD, Impatt diodes
    • Schottky, varactor diodes
    • Magnetron, Carcinotron
    • FETs, HEMTs

Indirect

  • Multiplication
  • Nonlinearities

Difficulties:

current, temperature, contact resistance, efficiency, noise

main features of thz radiation
Main Features of THz Radiation
  • Non ionizing
  • Strong interaction with molecules
  • Transmitted through many materials
  • Higher resolution than microwaves
applications in spectroscopy
Applications in Spectroscopy

Physics: THz Time Domain Spectroscopy, dynamics of electrons, holes, phonons

applications in spectroscopy10
Applications in Spectroscopy

Chemistry: chemical reactions, combustion, pollution, environment control

(Grischkowski, Oklahoma State Univ.)

applications in spectroscopy11
Applications in Spectroscopy

Astronomy: atmospheric window, detection of molecules, atoms, ionized gas

slide12

Applications in Telecommunications

TeraHertz antennas, wireless communication

Progr. Quant. Electr. 28, 1 (2004)

slide13

Applications in Art

http://www.spiegel.de

applications in imaging t ray
Applications in Imaging (T-Ray)

Inspection materials/devices/systems

Industry

(Planken, Univ. Delft)

applications in imaging t ray15
Applications in Imaging (T-Ray)

Medicine

Tooth decay

(TeraView)

applications in imaging t ray16
Applications in Imaging (T-Ray)

Medicine

Dermatology

(Teraview)

slide17

Applications in Imaging (T-Ray)

Security

Courtesy of Teraview

1 thz nanotransistors
1. THz Nanotransistors
  • … exploiting plasma waves
experiments on ingaas hemts
Experiments on InGaAs HEMTs

Origin of the peaks?

Appl. Phys. Lett. 80, 3433 (2002)

thz oscillations from plasma waves
THz oscillations from plasma-waves

3D plasma oscillations

Analogy : harmonic oscillator

Tunable frequency with Vg

Practical applications :

High Electron Mobility Transistor

travelling plasma waves22
Travelling plasma waves

Mascaret over the Dordogne river

http://www.archaero.com/mascaret.htm

stationary plasma waves
Stationary plasma waves

n = 1 f = 0.9 THz

n = 3 f = 2.7 THz

plasma synchronization by optical beating
Plasma synchronization by optical beating

THz

beating

Appl. Phys. Lett. 89, 201101 (2006)

detection of thz beating thz generation

Frequency (GHz)

Detection of THz beating + THz generation

Experiments

(detection)

Simulation

(generation+detection)

δ VDS

⟨VDS⟩

Appl. Phys. Lett. 89, 201101 (2006)

resonant frequency vs swing voltage

5f0

3f0

f0

Resonant frequency vs swing voltage

Provides frequency tuning

IEEE J. Sel. Top. Quant. Electron. 14, 491 (2008)

enhancing detection
Enhancing detection

Simulation

Experiments

Modeling

Journ. Appl. Phys. 106, 013717 (2009)

thz imaging with hemt
THz imaging with HEMT

Non resonant detection

F. Teppe et al., to be published (2009)

2 terahertz maser
2. TeraHertz MASER
  • … or exploiting the optical-phonon transit-time resonance in nitrides
scattering rates in gan at t 10 k
Scattering rates in GaN at T=10 K

low energies: acoustic and impurity scattering

high energies: optical phonon emission

J. Appl. Phys. 89, 1161 (2001)

the optical phonon transit time resonance
The optical-phonon transit-time resonance

τ -

τ +

Scattering rate

optical

phonon

acceleration τE

Energy

τ- : Average relaxation time

τE : Carrier transit time

τ+ : Time for optical phonon emission

advantages of nitrides
Advantages of nitrides

Stronger electron-phonon coupling

Much sharper threshold

J. Appl. Phys. 89, 1161 (2001)

slide35

InN,

T=10 K

slide36

InN,

T=10 K

slide37

InN,

T=10 K

slide38

InN,

T=10 K

summary of amplification bands
Summary of amplification bands

Phys. Rev. B 76, 045333 (2007)

design of a cavity and emitted power
Design of a cavity and emitted power

low E

large E

Gain depends on the electric field

conclusions
Conclusions
  • Exciting field for theory and experiments
  • Junction electronics/optics
  • New phenomena, materials, devices, systems
sujet de stage
Sujet de stage

« Etude expérimentale des oscillations Gunn et de plasma téraHertz dans des composants de la micro-électronique »