In this note, we are going to know about Single Electron Transistor or SET, about its structure, working, advantages, disadvantages, and applications as well. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.
Author Name: Arun Paul.
What is Single Electron Transistor in Nanotechnology or SET?
A Single Electron Transistor (SET) is a nanoscale electrical device that controls the flow of individual electrons. It is a key component in nanoelectronics, with applications including quantum computing, ultra low power circuits, and high precision sensors.
Structure of SET or Single Electron Transistor Diagram
The Single Electron Transistor consists these sections –
- Source and Drain Electrodes – It is connected to a nano sized island (quantum dot) where electrons tunnel through.
- Quantum Dot (Island) – It is a small conductive region where electrons are confined.
- Tunnel Junctions – Thin insulating barriers that allow electrons to tunnel one at a time due to the Coulomb blockade effect.
- Gate Electrode – Controls the energy levels of the quantum dot and modulates electron flow.
Specifications of SET
| Aspect | Value |
|---|---|
| Quantum Dot (Island) Size | 1–10 nm |
| Tunnel Junction Thickness | 1–2 nm |
| Operating Temperature | < 1 K |
| Gate Capacitance | 10–100 aF (attofarads) |
| Charging Energy | 10–100 meV |
| Source-Drain Voltage | < 1 mV |
Single Electron Transistor Working Principle
SET works using the Coulomb barrier effect and quantum tunneling. At the nanoscale, the quantum dot’s charging energy increases significantly, preventing multiple electrons from flowing through the device at the same time. Coulomb blockade ensures that electrons are transported one at a time. Furthermore, quantum mechanics allows electrons to tunnel through thin insulating barriers (tunnel junctions) between the source, quantum dot, and drain when certain voltage requirements are fulfilled.
The gate electrode is vital in controlling the device’s functionality. The energy levels of the quantum dot can be fine tuned by altering the voltage provided to the gate, allowing a single electron to pass through the dot when desired. Because of their fine control over electron flow, SETs are both energy efficient and sensitive, making them ideal for applications in nanoelectronics and quantum computing.
Advantages of Single Electron Transistor or SET
Here are the advantages of single electron transistor or SET –
- This transistor can operates at ultra low level of energy.
- It can easily detect individual electrons. For this reason, it is used for sensitive applications.
- This type of transistor support quantum state manipulation.
Single Electron Transistor Applications
Here are the application of single electron transistor –
- Used in energy efficient nano devices.
- Used in bio electronics.
- Used in Quantum Computing system.