Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742711
G. Baraff
We study the effect of an imaginary potential and (separately) of a finite coherence length on the transmission, reflection, and capture fractions for a thermal distribution of carriers incident on a single quantum well. The formalism used is closely related to one used by Kuhn and Mahler for the same purpose. Closed form expressions are obtained for the three transport fractions resulting from a single incident beam. Three independent fitting parameters are used in this formalism, namely, the size of the imaginary potential, the extent it penetrates into the barriers adjacent to the well, and the phase coherence length. This last is a length scale associated with a correlation function that appears when the phase of the wave function is treated as a stochastic variable. We show that the parameters can be chosen so that the transport fractions agree with those calculated from first principles, and show how a shortening of the coherence length, e.g., by electron-electron interactions that have been left out of the first principles calculation, destroys the resonant behavior of these fractions predicted by Brum and Bastard.
{"title":"Quantum mechanical aspects of vertical transport and capture in quantum wells","authors":"G. Baraff","doi":"10.1109/IWCE.1998.742711","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742711","url":null,"abstract":"We study the effect of an imaginary potential and (separately) of a finite coherence length on the transmission, reflection, and capture fractions for a thermal distribution of carriers incident on a single quantum well. The formalism used is closely related to one used by Kuhn and Mahler for the same purpose. Closed form expressions are obtained for the three transport fractions resulting from a single incident beam. Three independent fitting parameters are used in this formalism, namely, the size of the imaginary potential, the extent it penetrates into the barriers adjacent to the well, and the phase coherence length. This last is a length scale associated with a correlation function that appears when the phase of the wave function is treated as a stochastic variable. We show that the parameters can be chosen so that the transport fractions agree with those calculated from first principles, and show how a shortening of the coherence length, e.g., by electron-electron interactions that have been left out of the first principles calculation, destroys the resonant behavior of these fractions predicted by Brum and Bastard.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"172 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116158154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742730
S. Amakawa, M. Fujishima, K. Hoh
Issues pertaining to single-electron tunneling through an asymmetrical tunnel barrier are discussed. A simple means of incorporating the change in the barrier shape accompanying a tunneling event into calculation of tunnel resistance is proposed. Simulation results show that directionality of tunneling through asymmetrical tunnel barriers is not as strong as reported previously, and that even an unphysical effect could arise if the barrier shape change is neglected.
{"title":"Single-electron tunneling through an asymmetrical tunnel barrier","authors":"S. Amakawa, M. Fujishima, K. Hoh","doi":"10.1109/IWCE.1998.742730","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742730","url":null,"abstract":"Issues pertaining to single-electron tunneling through an asymmetrical tunnel barrier are discussed. A simple means of incorporating the change in the barrier shape accompanying a tunneling event into calculation of tunnel resistance is proposed. Simulation results show that directionality of tunneling through asymmetrical tunnel barriers is not as strong as reported previously, and that even an unphysical effect could arise if the barrier shape change is neglected.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124119372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742697
M. Kirihara, K. Taniguchi
It is very difficult to fabricate an SET transistor with large gate capacitance and and small junction capacitance. The authors develop a hybrid circuit simulator to address these problems. The hybrid circuit simulator is composed of a conventional circuit simulator, SPICE, and a SET circuit simulator.
{"title":"Hybrid circuit simulator for combined single electronic and conventional circuit elements","authors":"M. Kirihara, K. Taniguchi","doi":"10.1109/IWCE.1998.742697","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742697","url":null,"abstract":"It is very difficult to fabricate an SET transistor with large gate capacitance and and small junction capacitance. The authors develop a hybrid circuit simulator to address these problems. The hybrid circuit simulator is composed of a conventional circuit simulator, SPICE, and a SET circuit simulator.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126425848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742738
F. Buot, R. Rendell, E. Snow, P. Campbell, D. Park, C. Marrian, R. Magno
The ideal tunneling operation, materials, and geometrical design considerations for novel field-effect transistors which do not employ dopants of any kind are given. Nonideal effects on the performance, such as the effects of scattering and excess-space charge, are also simulated.
{"title":"Fundamental operation and design considerations for metal-oxide tunnel transistors","authors":"F. Buot, R. Rendell, E. Snow, P. Campbell, D. Park, C. Marrian, R. Magno","doi":"10.1109/IWCE.1998.742738","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742738","url":null,"abstract":"The ideal tunneling operation, materials, and geometrical design considerations for novel field-effect transistors which do not employ dopants of any kind are given. Nonideal effects on the performance, such as the effects of scattering and excess-space charge, are also simulated.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116981960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742753
A. Jungel, C. Pohl
In this paper, the authors discuss two modern semiconductor models: the energy-transport and the quantum hydrodynamic equations. The energy-transport models consist of the conservation laws for mass and energy for the electrons, coupled self-consistently to the Poisson equation. The quantum hydrodynamic equations consist of the conservation laws for mass, momentum and energy, including the Poisson equation.
{"title":"Numerical simulation of semiconductor devices: energy-transport and quantum hydrodynamic modeling","authors":"A. Jungel, C. Pohl","doi":"10.1109/IWCE.1998.742753","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742753","url":null,"abstract":"In this paper, the authors discuss two modern semiconductor models: the energy-transport and the quantum hydrodynamic equations. The energy-transport models consist of the conservation laws for mass and energy for the electrons, coupled self-consistently to the Poisson equation. The quantum hydrodynamic equations consist of the conservation laws for mass, momentum and energy, including the Poisson equation.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133391355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742698
N. Mori, T. Ezaki, C. Hamaguchi
Electronic states in quantum dots containing N electrons are calculated by numerically diagonalizing the N-electron Hamiltonian in order to study the effect of the dot-shape on the electronic states. Energy relaxation time through longitudinal-acoustic phonon emission is also calculated using the exact eigenstates.
{"title":"Modeling of electronic states and electron-phonon interaction in quantum dots","authors":"N. Mori, T. Ezaki, C. Hamaguchi","doi":"10.1109/IWCE.1998.742698","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742698","url":null,"abstract":"Electronic states in quantum dots containing N electrons are calculated by numerically diagonalizing the N-electron Hamiltonian in order to study the effect of the dot-shape on the electronic states. Energy relaxation time through longitudinal-acoustic phonon emission is also calculated using the exact eigenstates.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131708821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742728
Z. Wang, M. Iwanaga, T. Miyoshi
We propose a novel approach based on interacting Green's functions on a tight-binding basis to analyze the current fluctuation through a semiconductor quantum dot, where electron-electron interaction is represented by the retarded self-energy.
{"title":"Quantum transport modeling of current fluctuations in semiconductor quantum dots","authors":"Z. Wang, M. Iwanaga, T. Miyoshi","doi":"10.1109/IWCE.1998.742728","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742728","url":null,"abstract":"We propose a novel approach based on interacting Green's functions on a tight-binding basis to analyze the current fluctuation through a semiconductor quantum dot, where electron-electron interaction is represented by the retarded self-energy.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130286791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742716
David K. Ferry, H. Grubin
In this paper, the arguments for various sizes of electrons is considered for semiconductor devices. In particular, in the quasi-two-dimensional electron gas of ballistic quantum dots, it is argued that the effective size of the electron packet is only /spl lambda//sub F///spl pi/, a value providing an almost minimum uncertainty packet. This size also reflects the "squeezing" of the packet in two dimensions as the carrier density is increased.
{"title":"Electrons in semiconductors: how big are they?","authors":"David K. Ferry, H. Grubin","doi":"10.1109/IWCE.1998.742716","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742716","url":null,"abstract":"In this paper, the arguments for various sizes of electrons is considered for semiconductor devices. In particular, in the quasi-two-dimensional electron gas of ballistic quantum dots, it is argued that the effective size of the electron packet is only /spl lambda//sub F///spl pi/, a value providing an almost minimum uncertainty packet. This size also reflects the \"squeezing\" of the packet in two dimensions as the carrier density is increased.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113969530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742732
G. Iannaccone, C. Ungarelli, M. Macucci
We have performed a numerical simulation of a system made of a quantum dot and a nearby quantum point contact defined, by means of depleting metal gates, in a two-dimensional electron gas at a GaAs/AlGaAs heterointerface. As recent experiments have shown, such a system can be used as a non-invasive detector of single charges being added to or removed from a quantum dot. We have computed the occupancy of the dot and the resistance of the quantum wire as a function of the voltage applied to the plunger gate, and have derived design criteria for achieving optimal sensitivity.
{"title":"Simulation and design of a single charge detector","authors":"G. Iannaccone, C. Ungarelli, M. Macucci","doi":"10.1109/IWCE.1998.742732","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742732","url":null,"abstract":"We have performed a numerical simulation of a system made of a quantum dot and a nearby quantum point contact defined, by means of depleting metal gates, in a two-dimensional electron gas at a GaAs/AlGaAs heterointerface. As recent experiments have shown, such a system can be used as a non-invasive detector of single charges being added to or removed from a quantum dot. We have computed the occupancy of the dot and the resistance of the quantum wire as a function of the voltage applied to the plunger gate, and have derived design criteria for achieving optimal sensitivity.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129202706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-10-19DOI: 10.1109/IWCE.1998.742694
Xuedong Hu, W. Potz
We briefly review our theoretical efforts to predict and evaluate possible coherent control schemes in semiconductor heterostructures, emphasizing some of our most recent results. We show that, given suitable light sources, coherent control of optical absorption, optical gain, and coherent control of phonon emission can be achieved in relatively simple semiconductor heterostructures.
{"title":"Coherent control of interband transitions in semiconductor quantum wells","authors":"Xuedong Hu, W. Potz","doi":"10.1109/IWCE.1998.742694","DOIUrl":"https://doi.org/10.1109/IWCE.1998.742694","url":null,"abstract":"We briefly review our theoretical efforts to predict and evaluate possible coherent control schemes in semiconductor heterostructures, emphasizing some of our most recent results. We show that, given suitable light sources, coherent control of optical absorption, optical gain, and coherent control of phonon emission can be achieved in relatively simple semiconductor heterostructures.","PeriodicalId":357304,"journal":{"name":"1998 Sixth International Workshop on Computational Electronics. Extended Abstracts (Cat. No.98EX116)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116018366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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