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Title: A quantum-dot heterostructure transistor with enhanced maximum drift velocity of electrons

Abstract

A new type of heterotransistor based on an AlGaAs/GaAs/InAs/GaAs/InAs structure with a layer of InAs quantum dots embedded directly into the GaAs channel is fabricated. High values of the maximum saturation current (up to 35 A/cm) and transconductance (up to 1300 mS/mm) are attained. The specific features of the current-voltage characteristics of the new device are explained in the context of a model that takes into account the ionization of quantum dots in high electric fields and tenfold enhancement of the electron drift velocity in a structure with an InAs quantum-dot layer in the vicinity of an AlGaAs/GaAs heterojunction.

Authors:
 [1]; ; ;  [2]
  1. Russian Academy of Sciences, Institute of Microwave Semiconductor Electronics (Russian Federation)
  2. Semiconductor Physics Institute (Lithuania)
Publication Date:
OSTI Identifier:
21088573
Resource Type:
Journal Article
Resource Relation:
Journal Name: Semiconductors; Journal Volume: 40; Journal Issue: 3; Other Information: DOI: 10.1134/S1063782606030201; Copyright (c) 2006 Nauka/Interperiodica; Article Copyright (c) 2006 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM ARSENIDES; ELECTRON DRIFT; ELECTRONS; GALLIUM ARSENIDES; HETEROJUNCTIONS; INDIUM ARSENIDES; IONIZATION; LAYERS; QUANTUM DOTS; TRANSISTORS; VELOCITY

Citation Formats

Mokerov, V., Pozela, J., E-mail: pozela@spi.pfi.lt, Pozela, K., and Juciene, V. A quantum-dot heterostructure transistor with enhanced maximum drift velocity of electrons. United States: N. p., 2006. Web. doi:10.1134/S1063782606030201.
Mokerov, V., Pozela, J., E-mail: pozela@spi.pfi.lt, Pozela, K., & Juciene, V. A quantum-dot heterostructure transistor with enhanced maximum drift velocity of electrons. United States. doi:10.1134/S1063782606030201.
Mokerov, V., Pozela, J., E-mail: pozela@spi.pfi.lt, Pozela, K., and Juciene, V. Wed . "A quantum-dot heterostructure transistor with enhanced maximum drift velocity of electrons". United States. doi:10.1134/S1063782606030201.
@article{osti_21088573,
title = {A quantum-dot heterostructure transistor with enhanced maximum drift velocity of electrons},
author = {Mokerov, V. and Pozela, J., E-mail: pozela@spi.pfi.lt and Pozela, K. and Juciene, V.},
abstractNote = {A new type of heterotransistor based on an AlGaAs/GaAs/InAs/GaAs/InAs structure with a layer of InAs quantum dots embedded directly into the GaAs channel is fabricated. High values of the maximum saturation current (up to 35 A/cm) and transconductance (up to 1300 mS/mm) are attained. The specific features of the current-voltage characteristics of the new device are explained in the context of a model that takes into account the ionization of quantum dots in high electric fields and tenfold enhancement of the electron drift velocity in a structure with an InAs quantum-dot layer in the vicinity of an AlGaAs/GaAs heterojunction.},
doi = {10.1134/S1063782606030201},
journal = {Semiconductors},
number = 3,
volume = 40,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • Back-action in the readout of quantum bits is an area that requires a great deal of attention in electron spin based-quantum bit architecture. We report here back-action measurements in a silicon device with quantum dots and a single-electron transistor (SET) charge sensor. We observe the back-action-induced excitation of electrons from the ground state to an excited state in a quantum dot. Our measurements and theoretical fitting to the data reveal conditions under which both suitable SET charge sensor sensitivity for qubit readout and low back-action-induced transition rates (less than 1 kHz) can be achieved.
  • It is shown that the optical-phonon momentum quantization in a GaAs quantum well resulting from the introduction of an InAs quantum-dot barrier layer provides for the elimination of inelastic scattering of electrons by optical phonons and, thus, makes the acceleration of electrons above the saturation drift velocity possible. It is shown experimentally that the maximum drift velocity of electrons in high electric fields in AlGaAs/GaAs heterostructure with InAs quantum-dot barriers introduced into the GaAs quantum well exceeds the saturation drift velocity in bulk GaAs by as much as a factor of 10. Such a rise in the maximum drift velocitymore » of electrons ensures increased maximum current density, transconductance, and cutoff frequency of the heterostructure field-effect transistor with quantum dots.« less
  • The dependence of the electron mobility and drift velocity on the growth conditions, thickness, and doping of an InAs insert placed at the center of the quantum well in a selectively doped InAlAs/InGaAs/InAlAs heterostructure has been investigated. Record enhancement of the maximum drift velocity to (2-4) Multiplication-Sign 10{sup 7} cm/s in an electric field of 5 Multiplication-Sign 10{sup 3} V/cm has been obtained in a 17-nm-wide quantum well with an undoped 4-nm-thick InAs insert. In the structures with additional doping of the InAs insert, which facilitates an increase in the density of electrons in the quantum well to 4.0 Multiplication-Signmore » 10{sup 12} cm{sup -2}, the maximum drift velocity is as high as 2 Multiplication-Sign 10{sup 7} cm/s in an electric field of 7 Multiplication-Sign 10{sup 3} V/cm.« less
  • It is experimentally found that the maximum drift velocity of electrons in quantum wells of differently arranged AlGaAs/GaAs heterostructures and pseudoamorphous Al{sub 0.36}Ga{sub 0.64}As/In{sub 0.15}Ga{sub 0.85} As heterostructures is higher than the maximum drift velocity of electrons in bulk materials. It is established that no negative differential conductivity is exhibited by the field dependence of the drift velocity of two-dimensional electrons in GaAs and In{sub 0.15}Ga{sub 0.85}As. The drift velocity in the GaAs quantum well is saturated in fields several times higher than the field corresponding to the {gamma}-L intervalley transitions of electrons in bulk GaAs.
  • The field dependence of drift velocity of electrons in quantum wells of selectively doped In{sub 0.5}Ga{sub 0.5}As/Al{sub x}In{sub 1-x}As and In{sub 0.2}Ga{sub 0.8}As/Al{sub x}Ga{sub 1-x}As heterostructures is calculated by the Monte Carlo method. The influence of varying the molar fraction of Al in the composition of the Al{sub x}Ga{sub 1-x}As and Al{sub x}In{sub 1-x}As barriers of the quantum well on the mobility and drift velocity of electrons in high electric fields is studied. It is shown that the electron mobility rises as the fraction x of Al in the barrier composition is decreased. The maximum mobility in the In{sub 0.5}Ga{submore » 0.5}As/In{sub 0.8}Al{sub 0.2}As quantum wells exceeds the mobility in a bulk material by a factor of 3. An increase in fraction x of Al in the barrier leads to an increase in the threshold field E{sub th} of intervalley transfer (the Gunn effect). The threshold field is E{sub th} = 16 kV/cm in the In{sub 0.5}Ga{sub 0.5}As/Al{sub 0.5}In{sub 0.5}As heterostructures and E{sub th} = 10 kV/cm in the In{sub 0.2}Ga{sub 0.8}As/Al{sub 0.3}Ga{sub 0.7}As heterostructures. In the heterostructures with the lowest electron mobility, E{sub th} = 2-3 kV/cm, which is lower than E{sub th} = 4 kV/cm in bulk InGaAs.« less