POLAR-OPTICAL PHONON ENHANCEMENT OF HARMONIC GENERATION IN SCHOTTKY DIODES

Polar-optical phonons have an important influence on polar semiconductor device behavior, in polar crystals at very high frequency, because they directly perturb the effective material permittivity in the vicinity of the transverse polar-optical vibration frequency. This phenomenon leads to dramatic nonlinear effects on the resistive and the reactive physics at the Schottky barrier interface. Hence this physical effect provides a mechanism with the potential for producing significant levels of power at higher harmonics. We have established a simulator that combines the modified harmonic-balance circuit analysis technique with a polar-optical phonon hydrodynamic transport model to determine the maximum power generation and/or power efficiency in the second harmonic. An abrupt junction model that includes the polar-optical phonon dynamics in a depletion layer was developed and utilized in this study. Simulation results have revealed a dramatic influence on the second harmonic power of the Schottky diode at the transverse polar-optical frequency and in the vicinity of one-half of the transverse polar-optical frequency. The transverse polar-optical frequency in GaAs is 7.78 THz and this is a rather high for practical applications. Bismuth trisulfide ( Bi 2 S 3) has been identified as a polar material that has the transverse polar-optical frequency on the order of 300 GHz, which is in a range more suited to THz-frequency multiplier applications. The dependence of the second harmonic power of the Schottky diode on the frequency demonstrates two enhanced peaks in the vicinity of the transverse polar-optical frequency. These preliminary results suggest that Bi 2 S 3 Schottky diode based multipliers have potential as enhanced sources within the terahertz regime.

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Polar Optical Phonon Instability and Intervalley Transfer in Gallium Nitride

MRS Proceedings ◽

10.1557/proc-512-549 ◽

1998 ◽

Vol 512 ◽

Cited By ~ 2

Author(s):

B. E. Foutz ◽

S. K. O'leary ◽

M. S. Shur ◽

L. F. Eastman ◽

B. L. Gelmont ◽

...

Keyword(s):

Gallium Nitride ◽

Analytical Model ◽

Optical Phonon ◽

Room Temperature ◽

Phonon Scattering ◽

Polar Optical Phonon ◽

Scattering Mechanism ◽

Loss Mechanism ◽

One Dimensional ◽

Optical Phonon Scattering

ABSTRACTWe develop a simple, one-dimensional, analytical model, which describes electron transport in gallium nitride. We focus on the polar optical phonon scattering mechanism, as this is the dominant energy loss mechanism at room temperature. Equating the power gained from the field with that lost through scattering, we demonstrate that beyond a critical electric field, 114 kV/cm at T = 300 K, the power gained from the field exceeds that lost due to polar optical phonon scattering. This polar optical phonon instability leads to a dramatic increase in the electron energy, this being responsible for the onset of intervalley transitions. The predictions of our analytical model are compared with those of Monte Carlo simulations, and are found to be in satisfactory agreement.

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