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Recent RF/Microwave and Device Research Project
Quantum Simulation of Resonant Tunneling
We have developed under Cray support a quantum simulator for the
modeling of quantum transport in layered heterostructure
devices. This simulator accounts for 3D multiple
sequential scattering (MSSCAT) in semiconductors.
Scattering processes considered include polar phonon
scattering, acoustic phonon scattering, intervalley scattering,
electron-electorn scattering, alloy scattering and interface
roughness scattering.
Under Texas Instrument support
the MSSCAT simulator was extended to multi-band transport.
Current work are focusing on the application of this
simulator to the design of infra-red laser diodes.
For more detailed information on this quantum simulator
check the
MSSCAT homepage.
Examples of test runs are availables.
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Features of MSSCAT demonstrated above are:
Hartree self-consistent potential,
impact of interface roughness scattering on the
electron transmission and I-V, and Gamma to X elastic
scattering
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High Frequency Response of Resonant Tunneling
We have reported quantum simulations
(W.-R. Liou and P. Roblin IEEE Trans. Elec. Dev.
41,p.1098 (1994))
based on the
self-consistent solution of the Poisson and Schrodinger equations
for both DC and AC which predicts an increase of the RTD
capacitance in the negative differential conductance (NDC)
region due to the discharging of the well charge.
We have conducted microwave measurements on a RTD
for which the conditions for stability
have been succesfully met.
The RTD capacitance is extracted
from the scattering parameters and the
expected increase of the RTD capacitance is
observed in the NDC region as
predicted by the theory and in agreement with
a previous experimental observation
(C. V. Sammut and N. J. Cronin,
IEEE Microwave and Guided Wave Letters,
2, p.486 (1992)).
Transient simulations of an RTD with its DC biasing circuit
were also conducted to demonstrate
the impact of the peak of the capacitance
on the time-average current-voltage characteristic and
the microwave oscillations in the NDC region.
(Siraj Akthar, Patrick Roblin)
This quantum simulator was also extended to account for infra-red
absorption and emission.
Application to the design of far infra-red laser diodes.
For more detailed information on these quantum simulations check the
HTML link.
Patrick Roblin (roblin@ee.eng.ohio-state.edu)