single electron transistor
DESCRIPTION
single elctron transistors are the future of quantum computingTRANSCRIPT
In 19th century Shockley, Brattain, Bardeen invented the information age “the transistor”.In 19th century Shockley, Brattain, Bardeen invented the information age “the transistor”.
“Moore’s law” states that transistor density on integrated circuit doubles at every two years.“Moore’s law” states that transistor density on integrated circuit doubles at every two years.
A single-electron transistor consists of a small conducting island connected to an source and drain leads by tunnel junctions and connected to one or more gates.
Source and drain electrodes are attached to the island via a tunnel barrier.
operation relies on single electron tunneling through a Nano scale junction.
many electrons (1000-10, 000 electrons) simultaneously participate from the source to the drain current in the conventional MOSFETs, electrons in SET devices are transferred one-by-one through the channel.
δ
Ec
IF ENERGY IS NOT AVAILABLE TRANSPORT IS BLOCKED
Requirement on resistance
∆t=RC typical time to charge/discharge of an island∆E ∆t=(e^2/C)RC> h/(2π) Heisenberg uncertainty principle
To observe SET effects this condition must be fulfilled EC>>kT
2e
hRQ
ee
kTC
1
Electrostatics gives the following relation between the different potentials and the charge Q on the island (VD =0)
Where the total charge is
This equation can be written in the form
with
i.e., the potential on the dot is determined by the charge residing on it and by the induced potential Vext of the source, drain and gate.
Vext = CgVg/CVext = CgVg/C
CONSTANT INTERACTION MODEL
CVi-CgVg=QCVi-CgVg=Q
Sketch of the electrostatic potential energy experienced by an electron moving at the interface between GaAs and AlGaAs
Space–energy diagrams of a single-electron transistor in which electrons are confined between two tunneling barriers. The plunger gate voltage is
increased from (a) to (c).
Schematic drawing of a SET. Wires are connected to source and drain contacts to pass current through the 2DEG at the GaAs/AlGaAs interface. Wires are also connected to the confining electrodes to bias them negatively and to the gate electrode that controls the electrostatic energy of the confined electrons.
Schematic drawing of a SET. Wires are connected to source and drain contacts to pass current through the 2DEG at the GaAs/AlGaAs interface. Wires are also connected to the confining electrodes to bias them negatively and to the gate electrode that controls the electrostatic energy of the confined electrons.
With reference to previous slide
Conductance of a SET as a function of the gate voltage. The spacing between the peaks is the voltage necessary to add one electron to
the artificial atom.
Initial device structure of SET
SIMOX wafer. A type of
SOI.
Conductance oscillations as a function of the gatevoltage measured at 300 K at a drain voltage of 10 mV.
Conductance oscillations as a function
of the gate voltage measured at 40 K and at
adrain voltage of 10 mV.
Initial structure of the twin SETs before V-PADOX
Supersensitive electrometry:-Supersensitive electrometry:-If the source-drain voltage to a single- electron transistor is slightly above its Coulomb blockade threshold, source-drain current through the device is extremely sensitive to the gate voltage.
Microwave detection:-Microwave detection:-The videoresponse ("photoresponse") of single-electron systems to electromagnetic radiation with frequency f=Ec/h. Microwave has low frequency, and so low energy, so detection would not have been possible without SET.
TEMPERATURE STANDARDS NOVORAM
OTHER
GRID SYSTEM
SINGLE ELECTRON MOS
MEMORY
SCALING OF FLASH MEMORY
DEVICES
SET+CMOS+SETMOSSET+CMOS+SETMOS
SETs and CMOS transistors in SETMOS devices can provide enough gain and current drive to perform logic functions on a much smaller scale than possible with just an CMOS.
SETs and CMOS transistors in SETMOS devices can provide enough gain and current drive to perform logic functions on a much smaller scale than possible with just an CMOS.
More uses of electrometersMore uses of electrometers
Electrometers based on SET transistors could also be used to measure the quantum superposition of charge states in a island connected by a tunnel junction to a superconductor.
M. A. Kastner, “The single electron transistor and artificial atoms”, Ann. Phy. (Leipzig), vol. 9, pp. 885-895, 2000.
http://www.princeton.edu/~chouweb/newproject/research/SEM/Intro.html http://sergeyfrolov.wordpress.com/teaching/ Solid State Electronic Devices(sixth edition) Ben G. Streetman, Sanjay Kumar
Banerjee Electronics fundamental and applications(11th edition) D. Chattopadhyay, P.C. Rakshit http://source.theengineer.co.uk/ http://www.engineering.usu.edu/classes/ece/6430/fabrication1.pdf http://luciano.stanford.edu/~shimbo/set.html http://www.physicsandastronomy.pitt.edu/content/jeremy-levy Sketched oxide single-electron transistor", Guanglei Cheng, Pablo F. Siles, Feng Bi,
Cheng Cen,Daniela F. Bogorin, Chung Wung Bark, Chad M. Folkman, Jae-Wan Park, Chang-Beom Eom, Gilberto Medeiros-Ribeiro and Jeremy Levy, Nature Nanotechnology 6, 343 (2011).
users.physik.fu-berlin.de/~pascual/.../SS20314-Lesung%2010d.PDF http://insti.physics.sunysb.edu/physics/forms/profilesearch.cgi?
lastname=Averin&firstname=Dmitri
M. A. Kastner, “The single electron transistor and artificial atoms”, Ann. Phy. (Leipzig), vol. 9, pp. 885-895, 2000.
http://www.princeton.edu/~chouweb/newproject/research/SEM/Intro.html http://sergeyfrolov.wordpress.com/teaching/ Solid State Electronic Devices(sixth edition) Ben G. Streetman, Sanjay Kumar
Banerjee Electronics fundamental and applications(11th edition) D. Chattopadhyay, P.C. Rakshit http://source.theengineer.co.uk/ http://www.engineering.usu.edu/classes/ece/6430/fabrication1.pdf http://luciano.stanford.edu/~shimbo/set.html http://www.physicsandastronomy.pitt.edu/content/jeremy-levy Sketched oxide single-electron transistor", Guanglei Cheng, Pablo F. Siles, Feng Bi,
Cheng Cen,Daniela F. Bogorin, Chung Wung Bark, Chad M. Folkman, Jae-Wan Park, Chang-Beom Eom, Gilberto Medeiros-Ribeiro and Jeremy Levy, Nature Nanotechnology 6, 343 (2011).
users.physik.fu-berlin.de/~pascual/.../SS20314-Lesung%2010d.PDF http://insti.physics.sunysb.edu/physics/forms/profilesearch.cgi?
lastname=Averin&firstname=Dmitri
Biswadeep das 13000310065Sankhasubhra Sengupta 13000310091Arghya Acharjee 13000310104Ishika Biswas 13000310109