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Proceedings Paper

Highly nonlinear capacitance in quantum well/barrier heterostructures: application to harmonic multiplication at terahertz frequency
Author(s): V. Duez; Mohamed Henini; O. Vanbesien; J. Martyn Chamberlain; D. Lippens
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Paper Abstract

In this communication, we report on the design and the fabrication of quantum well barrier varactor structures with state of the art results in terms of capacitance ratio over a narrow voltage range. Basically, the fact to consider is a barrier cladded by two quantum wells with respect to a single barrier heterostructure. It has several consequences for the non linear character of the device. The capacitance mechanism is governed at low voltage by the electron population rates off the quantum well rather than the conventional depletion mode process. A true band gap capacitance engineering is here demonstrated with thee kinds of structures either in the InP material system with a InGaAs/InAs/AlAs heterostructure or in the GaAs material system with GaAs/InGaAs/AlAs pseudomorphic epilayers and lattice matched AlGaAs/GaAs/AlAs heterojunctions. Self- consistent simulations, based on the solution of Poisson and Schroedinger coupled equations system, were performed in order to calculate the electron wave function and the conduction band bending. High capacitance ratios can be predicted depending on material parameters and structure geometry. Test samples were then fabricated and rf tested. The devices very high capacitance ratios is excess of 5 to 1 over a 1 Volt range.

Paper Details

Date Published: 9 September 1999
PDF: 9 pages
Proc. SPIE 3828, Terahertz Spectroscopy and Applications II, (9 September 1999); doi: 10.1117/12.361023
Show Author Affiliations
V. Duez, Univ. des Sciences et Technologies de Lille (France)
Mohamed Henini, Univ. of Nottingham (United Kingdom)
O. Vanbesien, Univ. des Sciences et Technologies de Lille (France)
J. Martyn Chamberlain, Univ. of Nottingham (United Kingdom)
D. Lippens, Univ. des Sciences et Technologies de Lille (France)

Published in SPIE Proceedings Vol. 3828:
Terahertz Spectroscopy and Applications II
J. Martyn Chamberlain, Editor(s)

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