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Experimental study and modelling of AC characteristics of resonant Tunnelling Diodes

Roy Chowdhury, Dibakar (2008):
Experimental study and modelling of AC characteristics of resonant Tunnelling Diodes.
Darmstadt, Technische Universität, Technical University of Darmstadt,
[Ph.D. Thesis]

Abstract

In this thesis work, the small-signal response of the resonant tunneling diode at dierent frequencies is studied. It has been shown previously that because of the Coulomb interaction, the inherent limitation of the operating frequency and the charge relaxation (response) time of resonant tunneling diode (RTD) is not due to the resonant state lifetime [1], contrary to the general belief [2, 3]. Here we have experimentally shown that intrinsic response time of RTD is dierent than the resonant state lifetime and the operating frequencies of RTD is limited neither by the resonant state lifetime nor by the intrinsic response time. In fact we have experimentally demonstrated negative differential conductance (NDC) far beyond the resonant state lifetime limit which clearly proves that resonant tunneling exists at frequencies beyond the resonant state lifetime limit. Using the analytically derived equivalent circuit [1], the measured frequency response of the RTD admittances (conductances and susceptances) as well the special features of RTD capacitances at low frequencies are reproduced well. So we have experimentally shown that the proposed simple equivalent circuit for small signal analysis of RTD is correct and appropriate.

Item Type: Ph.D. Thesis
Erschienen: 2008
Creators: Roy Chowdhury, Dibakar
Title: Experimental study and modelling of AC characteristics of resonant Tunnelling Diodes
Language: English
Abstract:

In this thesis work, the small-signal response of the resonant tunneling diode at dierent frequencies is studied. It has been shown previously that because of the Coulomb interaction, the inherent limitation of the operating frequency and the charge relaxation (response) time of resonant tunneling diode (RTD) is not due to the resonant state lifetime [1], contrary to the general belief [2, 3]. Here we have experimentally shown that intrinsic response time of RTD is dierent than the resonant state lifetime and the operating frequencies of RTD is limited neither by the resonant state lifetime nor by the intrinsic response time. In fact we have experimentally demonstrated negative differential conductance (NDC) far beyond the resonant state lifetime limit which clearly proves that resonant tunneling exists at frequencies beyond the resonant state lifetime limit. Using the analytically derived equivalent circuit [1], the measured frequency response of the RTD admittances (conductances and susceptances) as well the special features of RTD capacitances at low frequencies are reproduced well. So we have experimentally shown that the proposed simple equivalent circuit for small signal analysis of RTD is correct and appropriate.

Place of Publication: Darmstadt
Publisher: Technische Universität
Uncontrolled Keywords: Resonant Tunnelling Diode, Coulomb interaction effect, resonant state lifetime, charge relaxation time, RTD response time, GHz, THz
Divisions: 18 Department of Electrical Engineering and Information Technology
18 Department of Electrical Engineering and Information Technology > Institute for Microwave Engineering and Photonics > Photonics and Optical Communications
18 Department of Electrical Engineering and Information Technology > Institute for Microwave Engineering and Photonics
Date Deposited: 17 Dec 2008 08:39
Official URL: urn:nbn:de:tuda-tuprints-11988
License: Creative Commons: Attribution-Noncommercial-No Derivative Works 3.0
Referees: Meissner, Prof. Dr. Peter and Hartnagel, Prof. Dr. Hans. L.
Refereed / Verteidigung / mdl. Prüfung: 23 June 2008
Alternative Abstract:
Alternative abstract Language
In dieser Arbeit wird die Kleinsignalantwort von resonanten Tunneldioden (RTD) bei verschiedenen Frequenzen untersucht. Es wurde bereits gezeigt, daß aufgrund von Coulomb-Wechselwirkungen die inhärente Begrenzung der Betriebsfrequenz und Relaxationszeit der Ladungsträger von RTD's nicht durch die Lebensdauer der resonanten Zustände [1] hervorgerufen wird, wie bisher angenommen wird [2,3]. Es wurde experimentell gezeigt, daß die intrinsische Zeitkonstante von RTD's unterschiedlich zu der Lebensdauer der resonanten Zustände ist und die Betriebsfrequenz von RTD's weder durch die Lebensdauer der resonanten Zustände noch durch die intrinsische Zeitkonstante begrenzt wird. Tatsächlich konnte der negative differentielle Leitwert weit über der Begrenzung durch die Lebensdauer der resonanten Zustände experimentell nachgewiesen werden, was deutlich belegt, daß resonantes Tunneln bei Frequenzen weit über der Begrenzung durch die Lebensdauer der resonanten Zustände existiert. Unter Anwendung des hergeleiteten Ersatzschaltbilds [1] werden die gemessenen Frequenzantworten der RTD Admittanzen und die speziellen Eigenschaften der RTD Kapazitäten bei niedrigen Frequenzen gut reproduziert. Es wurde experimentall nachgewiesen, daß das vorgeschlagene einfache Ersatzschaltbild für den Kleinsignalbetrieb korrekt und angemessen ist.German
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