New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Quantum dot

A quantum dot is a semiconductor nanostructure that confines the motion of conduction band electrons, valence band holes, or excitons (bound pairs of conduction band electrons and valence band holes) in all three spatial directions. The confinement can be due to electrostatic potentials (generated by external electrodes, doping, strain, impurities), the presence of an interface between different semiconductor materials (e.g. in core-shell nanocrystal systems), the presence of the semiconductor surface (e.g. semiconductor nanocrystal), or a combination of these. A quantum dot has a discrete quantized energy spectrum. The corresponding wave functions are spatially localized within the quantum dot, but extend over many periods of the crystal lattice. A quantum dot contains a small finite number (of the order of 1-100) of conduction band electrons, valence band holes, or excitons, i.e., a finite number of elementary electric charges.

Small quantum dots, such as colloidal semiconductor nanocrystals, can be as small as 2 to 10 nanometers, corresponding to 10 to 50 atoms in diameter and a total of 100 to 100,000 atoms within the quantum dot volume. Self-assembled quantum dots are typically between 10 and 50 nm in size. Quantum dots defined by lithographically patterned gate electrodes, or by etching on two-dimensional electron gases in semiconductor heterostructures can have lateral dimensions exceeding 100 nm. At 10 nm in diameter, nearly 3 million quantum dots could be lined up end to end and fit within the width of a human thumb.

Related Stories
 


Matter & Energy News

July 29, 2025

Scientists have cracked open a mysterious layer inside batteries, using cutting-edge 3D atomic force microscopy to capture the dynamic molecular structures at their solid-liquid interfaces. These once-invisible electrical double layers (EDLs) twist, ...
Deep beneath the Swiss-French border, the Large Hadron Collider unleashes staggering amounts of energy and radiation—enough to fry most electronics. Enter a team of Columbia engineers, who built ultra-rugged, radiation-resistant chips that now ...
Researchers are exploring AI-powered digital twins as a game-changing tool to accelerate the clean energy transition. These digital models simulate and optimize real-world energy systems like wind, solar, geothermal, hydro, and biomass. But while ...
Deep in Serbia's Jadar Valley, scientists discovered a mineral with an uncanny resemblance to Superman's Kryptonite both in composition and name. Dubbed jadarite, this dull white crystal lacks the ...
A team at KAUST has revealed that the short lifespan of aqueous batteries is primarily due to "free water" molecules triggering harmful chemical reactions at the anode. By adding affordable sulfate salts like zinc sulfate, they significantly reduced ...
Aalto University physicists in Finland have set a new benchmark in quantum computing by achieving a record-breaking millisecond coherence in a transmon qubit — nearly doubling prior limits. This development not only opens the door to far more ...
Imagine concrete that not only survives wildfires and extreme weather, but heals itself and absorbs carbon from the air. Scientists at USC have created an AI model called Allegro-FM that simulates billions of atoms at once, helping design futuristic ...
Scientists have used DNA's self-assembling properties to engineer intricate moiré superlattices at the nanometer scale—structures that twist and layer like never before. With clever molecular ...
Scientists have cracked a century-old physics mystery by detecting magnetic signals in non-magnetic metals using only light and a revamped laser technique. Previously undetectable, these faint magnetic “whispers” are now measurable, revealing ...
Using advanced metasurfaces, researchers can now twist light to uncover hidden images and detect molecular handedness, potentially revolutionizing data encryption, biosensing, and drug ...
A powerful new technique harnesses swirling plasma inside laser-blasted microtubes to produce record-breaking magnetic fields—rivaling those near neutron stars—all within a compact laboratory setup. This innovation promises to transform ...
A new leap in lab automation is shaking up how scientists discover materials. By switching from slow, traditional methods to real-time, dynamic chemical experiments, researchers have created a self-driving lab that collects 10 times more data, ...

Latest Headlines

updated 12:56 pm ET