When [[Electron|electrons]] or other particles are confined to extremely small regions within a [[Semiconductor|semiconductor]], typically only a few [[Length Scales|nanometers]] in diameter, physicists refer to these tiny regions as _quantum dots_. These structures are actively researched and used in a variety of applications, including display technology, photovoltaics, [[Quantum Simulation|quantum simulation]], and [[Quantum Computer|quantum computing]]. Quantum dots can be fabricated using several methods. One approach is _electrical gating_, which traps electrons by utilizing [[Electric Field|electric fields]] generated by small electrodes. Another technique is _self-assembly_, where quantum dots form spontaneously under specific conditions when a semiconductor is deposited on a material with a mismatched lattice structure. ![[quantum_dot.excalidraw.light.svg]] Electrons in quantum dots are confined to such tiny spaces that their behavior must be described using quantum mechanics. As a result, they exhibit [[Discreteness|discrete]] [[Energy|energy levels]], similar to those of [[Atom|atoms]]. This resemblance to atomic energy levels is why quantum dots are sometimes called _artificial atoms_—_artificial_ because they are engineered in the laboratory rather than occurring naturally. Just as [[Platform - Cold Atoms|cold atoms]] are trapped in [[Optical Lattice|optical lattices]], multiple electrons can be confined in arrays of quantum dots, where they can interact and tunnel between dots. These systems are explored for quantum simulation applications. Additionally, quantum dots can be used for quantum computing. According to [[DiVincenzo Criteria|DiVincenzo's criteria]], this requires the implementation of [[Quantum Gates|quantum gates]] between electrons. Such gates can be realized by controlling the [[Spin|spin]] of electrons and their interactions. Furthermore, quantum dots are employed to construct single-[[Photon|photon]] sources, which have various technological applications, including quantum cryptography, [[Quantum Communication|quantum communication]], and [[Quantum Metrology|quantum metrology]]. >[!read]- Further Reading >>- [[Electromagnetism]] >>- [[Length Scales]] >>- [[Semiconductor]] >[!ref]- References