International Research Journal of Engineering and Technology Volume: 04 Issue: 03 | Mar -2017
(IRJET)
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e-ISSN: 2395 -0056 p-ISSN: 2395-0072
Quantitative Modeling and Simulation of Single-Electron Transistor Shobhit Srivastava1, Ranjeet Pathak2 1M.Tech, 2Assistant
Student, Department of E&C Engineering, U.I.T. Allahabad, U.P (AKTU, University), India
Prof., Department of E&C Engineering, United Institute of Technology, Allahabad, Uttar Pradesh, India
------------------------------------------------------------------***----------------------------------------------------------------Abstract— The Single electron transistor (SET) is a new
nano scaled switching device that retains their scalability even on an atomic scale, which can offer ultra-low power consumption and high operating speed. SET has some attractive feature like unique coulomb blockade oscillation characteristic, and nano-scale size. It is seen that energy quantization mainly increases the Coulomb blockade area and Coulomb blockade oscillation periodicity, and thus, affects the SET circuit performance. The transfer of charge onto the island becomes quantized as the voltage increase, leading to the current, so-called coulomb staircase. For it two conditions are required mainly, in first condition the electron thermal fluctuations energy smaller than the coulomb energy and in second condition, the tunnel effect itself should be weak enough to prevent the charge of the tunneling electrons from becoming delocalized over the two electrodes of the junctions. The goal of this paper is to discuss about the DC characteristics of SET and the effect on characteristics of SET by variation of various physical parameters, is analyzed by MATLAB Simulink. Key Words—Quantum tunneling, Coulomb blockade (CB), quantum dot (QD), energy quantization, single electron transistor (SET).
1. INTRODUCTION Our world is without doubt built on the power of the transistor, a microscopic electronic switch used to perform digital logic. Right now, we are able to fit enough of these tiny devices onto a microchip to allow us to perform several billion operations in a single second, and are seeing a double in the speed of these microchips every 18 months. In order to keep up with this incredible rate of speed increase, transistors are becoming smaller and smaller, to the point where in the very near future, they will begin to not only feel the effects of quantum mechanics on their operation, but will have to take quantum mechanics into account as the dominant force in their engineering.
source and drain, allowing current to flow and thus turning the switch on. In a single electron transistor, however, charge moves by utilizing the effect of quantum tunneling. Instead of creating a channel of charge carriers between the source and drain electrodes, a single electron transistor utilizes two junctions where tunneling is the dominant method of electron transport to control the movement of single electrons through the device.
2. BASIC THEORY 2.1 QUANTUM TUNNELING A single electron transistor is based on the idea of quantum tunneling. In classical physics, when an electron is in a potential, it is unable to go anywhere, where the potential is higher than the energy of the electron fig.1.
Fig. 1: Classical theory of electron Tunneling However, According to the laws of quantum mechanics, when the size of the barrier is very small, the wave properties of the electron become relevant. And there is a non vanishing (larger than zero) probability for an electron on one side of the barrier to reach the other side.
Fig. 2: quantum tunneling of electron
Most transistors today are MOSFETs, where a semiconductor source and drain of one doping type are separated by an oppositely doped bulk semiconductor. The bulk semiconductor is then separated by a layer of oxide from a gate electrode between the source and the drain. As the gate bias is changed, the bias causes the formation of a conducting channel in the bulk material between the
2.2 COULOMB BLOCKADE
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In physics, a Coulomb blockade (abbreviated CB), named after Charles-Augustin de Coulomb's electrical force, is the increased resistance at small bias voltages of an electronic