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Quantum dots (QDs) – also called semiconductor nanocrystals, are semiconductor particles a few nanometres in size, having optical and electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology and materials science. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band.
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.
Gallium nitride () is a binary III/V direct bandgap semiconductor commonly used in blue light-emitting diodes since the 1990s. The compound is a very hard material that has a Wurtzite crystal structure. Its wide band gap of 3.4 eV affords it special properties for applications in optoelectronic, high-power and high-frequency devices. For example, GaN is the substrate which makes violet (405 nm) laser diodes possible, without requiring nonlinear optical frequency-doubling.
Gallium Nitride (GaN) is a wonder material which has widely transformed the world by enabling
energy-efficient white light-emitting diodes. Over the past decade, GaN has also emerged as one
of the most promising materials for developing power devices which ...
Two-dimensional (2D) materials are atomically thin crystals with exceptional mechanical, electrical and optical properties. Their unique characteristics originating from quantum confinement in the vertical dimension have attracted a strong interest for sci ...
We experimentally investigate the Lamb coupling constant C in InGaAlAs Quantum Wells active medium. An Optically-Pumped Vertical-External-Cavity Surface-Emitting Laser emitting at 1.54 mu m is designed to sustain the oscillation of two orthogonally polariz ...