Quantum dot

Definition:
A quantum dot is a nanoscale semiconductor particle, typically only a few nanometers in diameter, that exhibits quantum mechanical behaviour distinct from bulk semiconductors. Due to their small size, quantum dots have discrete, atom-like electronic energy levels.

Scientific context:
Quantum dots confine electrons and holes in all three spatial dimensions, creating quantized energy states. These energy levels can be controlled by adjusting the size, shape, and material of the quantum dot. Because of this, quantum dots are often referred to as “artificial atoms.”

Example in practice:

• In quantum dot single-photon sources, excitation of the dot leads to the emission of exactly one photon, which can be used in secure quantum communication.

• Spin qubits in quantum dots can be manipulated with magnetic or electric fields for quantum computing applications.

Did you know?
Quantum dots are also used in classical technologies, such as QLED displays and fluorescent bioimaging, thanks to their tunable light emission across the visible spectrum.