Terahertz electromagnetic pulses as probes for transient velocity overshoot in GaAs and Si

An ensemble Monte Carlo simulation is used to compare bulk electron ballistic transport in 6H - SiC and GaN materials. Electronic states within the conduction band valleys at Γ1, U, M, Γ3, and K are represented by nonparabolic ellipsoidal valleys centered on important symmetry points of the Brillouin zone. The large optical phonon energy (~120 meV) and the large intervalley energy separation between the Γ and satellite conduction band valleys suggest an increasing role for ballistic electron effects in 6H - SiC , especially when compared with most III-V semiconductors such as GaAs . Transient velocity overshoot has been simulated, with the sudden application of fields up to ~5×107 Vm -1, appropriate to the gate-drain fields expected within an operational field effect transistor. A peak-saturation drift velocity ratio of 2:1 is predicted for 6H - SiC material while that for GaN is 4:1. The electron drift velocity relaxes to the saturation value of ~2×105 ms -1 within 3 ps, for both crystal structures. The transient velocity overshoot characteristics are in fair agreement with other recent calculations.

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A comparison of transient velocity overshoot in Si and GaAs structures

Semiconductor Science and Technology ◽

10.1088/0268-1242/7/3b/102 ◽

1992 ◽

Vol 7 (3B) ◽

pp. B390-B393 ◽

Cited By ~ 5

Author(s):

D T Hughes ◽

R A Abram ◽

R W Kelsall ◽

A J Holden

Keyword(s):

Velocity Overshoot ◽

Transient Velocity

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COMPARISON OF HIGH FIELD STEADY STATE AND TRANSIENT ELECTRON TRANSPORT IN WURTZITE GaN, AlN AND InN

Modern Physics Letters B ◽

10.1142/s0217984907014103 ◽

2007 ◽

Vol 21 (25) ◽

pp. 1715-1721 ◽

Cited By ~ 7

Author(s):

H. ARABSHAHI ◽

M. R. BENAM ◽

B. SALAHI ◽

M. GHOLIZADEH

Keyword(s):

Steady State ◽

Electron Transport ◽

Critical Field ◽

Electron Velocity ◽

Wurtzite Phase ◽

Velocity Overshoot ◽

Ensemble Monte Carlo ◽

A Value ◽

Transient Velocity ◽

Effect Transistor

An ensemble Monte Carlo simulation is used to compare bulk electron transport in wurtzite phase GaN , AlN and InN materials. Electronic states within the conduction band valleys at the Γ1, U, M, Γ3 and K are represented by non-parabolic ellipsoidal valleys centered on important symmetry points of the Brillouin zone. For all materials, it is found that electron velocity overshoot only occurs when the electric field is increased to a value above a certain critical field, unique to each material. This critical field is strongly dependent on the material parameters. Transient velocity overshoot has also been simulated, with the sudden application of fields up to ~5 × 107 Vm -1, appropriate to the gate-drain fields expected within an operational field effect transistor. The electron drift velocity relaxes to the saturation value of ~1.4 × 105 ms -1 within 4 ps, for all crystal structures. The steady state and transient velocity overshoot characteristics are in fair agreement with other recent calculations.

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COMPARISON OF STEADY-STATE AND TRANSIENT ELECTRON TRANSPORT IN InAs, InP AND GaAs

Modern Physics Letters B ◽

10.1142/s0217984908016364 ◽

2008 ◽

Vol 22 (17) ◽

pp. 1695-1702 ◽

Cited By ~ 4

Author(s):

H. ARABSHAHI ◽

M. R. KHALVATI ◽

M. REZAEE ROKN-ABADI

Keyword(s):

Steady State ◽

Electron Transport ◽

Critical Field ◽

Electron Velocity ◽

Gaas Sample ◽

Velocity Overshoot ◽

Ensemble Monte Carlo ◽

A Value ◽

Transit Times ◽

Transient Velocity

An ensemble Monte Carlo simulation is used to compare high field electron transport in bulk InAs , InP and GaAs . In particular, velocity overshoot and electron transit times are examined. For all materials, we find that electron velocity overshoot only occurs when the electric field is increased to a value above a certain critical field, unique to each material. This critical field is strongly dependent on the material, about 400 kVm-1 for the case of GaAs , 300 kVm-1 for InAs and 700 kVm-1 for InP . We find that InAs exhibits the highest peak overshoot velocity and that this velocity overshoot lasts over the longest distances when compared with GaAs and InP . Finally, we estimate the minimum transit time across a 1 μm GaAs sample to be a bout 3 ps. Similar calculations for InAs and InP yield 2.2 and 5 ps, respectively. The steady-state and transient velocity overshoot characteristics are in fair agreement with other recent calculations.

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Transient velocity overshoot dynamics in GaAs for electric fields ≤ 200 kV/cm

Applied Physics Letters ◽

10.1063/1.109846 ◽

1993 ◽

Vol 63 (7) ◽

pp. 923-925 ◽

Cited By ~ 29

Author(s):

J. Son ◽

W. Sha ◽

J. Kim ◽

T. B. Norris ◽

J. F. Whitaker ◽

...

Keyword(s):

Electric Fields ◽

Velocity Overshoot ◽

Transient Velocity

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MONTE CARLO MODELING OF HOT ELECTRON TRANSPORT IN BULK AlAs, AlGaAs AND GaAs AT ROOM TEMPERATURE

Modern Physics Letters B ◽

10.1142/s0217984908016376 ◽

2008 ◽

Vol 22 (18) ◽

pp. 1777-1784 ◽

Cited By ~ 1

Author(s):

H. ARABSHAHI ◽

M. R. KHALVATI ◽

M. REZAEE ROKN-ABADI

Keyword(s):

Monte Carlo ◽

Drift Velocity ◽

Critical Field ◽

Electron Drift Velocity ◽

Electron Velocity ◽

Electron Drift ◽

Hot Electron ◽

Velocity Overshoot ◽

Transient Velocity ◽

Hot Electron Transport

The results of an ensemble Monte Carlo simulation of electron drift velocity response on the application field in bulk AlAs , AlGaAs and GaAs are presented. All dominant scattering mechanisms in the structure considered have been taken into account. For all materials, it is found that electron velocity overshoot only occurs when the electric field is increased to a value above a certain critical field, unique to each material. This critical field is strongly dependent on the material parameters. Transient velocity overshoot has also been simulated, with the sudden application of fields up to 1600 kVm-1, appropriate to the gate-drain fields expected within an operational field effect transistor. The electron drift velocity relaxes to the saturation value of ~105 ms-1 within 4 ps, for all crystal structures. The steady state and transient velocity overshoot characteristics are in fair agreement with other recent calculations.

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