Quantum wellA quantum well is a potential well with only discrete energy values. The classic model used to demonstrate a quantum well is to confine particles, which were initially free to move in three dimensions, to two dimensions, by forcing them to occupy a planar region. The effects of quantum confinement take place when the quantum well thickness becomes comparable to the de Broglie wavelength of the carriers (generally electrons and holes), leading to energy levels called "energy subbands", i.e.
Solar-cell efficiencySolar-cell efficiency refers to the portion of energy in the form of sunlight that can be converted via photovoltaics into electricity by the solar cell. The efficiency of the solar cells used in a photovoltaic system, in combination with latitude and climate, determines the annual energy output of the system. For example, a solar panel with 20% efficiency and an area of 1 m2 will produce 200 kWh/yr at Standard Test Conditions if exposed to the Standard Test Condition solar irradiance value of 1000 W/m2 for 2.
Electron avalancheAn electron avalanche is a process in which a number of free electrons in a transmission medium are subjected to strong acceleration by an electric field and subsequently collide with other atoms of the medium, thereby ionizing them (impact ionization). This releases additional electrons which accelerate and collide with further atoms, releasing more electrons—a chain reaction. In a gas, this causes the affected region to become an electrically conductive plasma.
PhotodetectorPhotodetectors, also called photosensors, are sensors of light or other electromagnetic radiation. There is a wide variety of photodetectors which may be classified by mechanism of detection, such as photoelectric or photochemical effects, or by various performance metrics, such as spectral response. Semiconductor-based photodetectors typically photo detector have a p–n junction that converts light photons into current. The absorbed photons make electron–hole pairs in the depletion region.
Quantum dot displayA quantum dot display is a display device that uses quantum dots (QD), semiconductor nanocrystals which can produce pure monochromatic red, green, and blue light. Photo-emissive quantum dot particles are used in LCD backlights or display color filters. Quantum dots are excited by the blue light from the display panel to emit pure basic colors, which reduces light losses and color crosstalk in color filters, improving display brightness and color gamut.
Google PixelGoogle Pixel is a brand of portable consumer electronic devices developed by Google that run either ChromeOS or the Android operating system. The main line of Pixel products consist of Android-powered smartphones, which have been produced since October 2016 as the replacement of the older Nexus, and of which the Pixel 7 is the current model. The Pixel brand also includes laptop and tablet computers, as well as several accessories, and was originally introduced in February 2013 with the Chromebook Pixel.
Photomultiplier tubePhotomultiplier tubes (photomultipliers or PMTs for short) are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. They are members of the class of vacuum tubes, more specifically vacuum phototubes. These detectors multiply the current produced by incident light by as much as 100 million times or 108 (i.e., 160 dB), in multiple dynode stages, enabling (for example) individual photons to be detected when the incident flux of light is low.
Secondary emissionIn particle physics, secondary emission is a phenomenon where primary incident particles of sufficient energy, when hitting a surface or passing through some material, induce the emission of secondary particles. The term often refers to the emission of electrons when charged particles like electrons or ions in a vacuum tube strike a metal surface; these are called secondary electrons. In this case, the number of secondary electrons emitted per incident particle is called secondary emission yield.
Pixel (1st generation)The Pixel and Pixel XL are a pair of Android smartphones designed, developed, and marketed by Google as part of the Google Pixel product line, succeeding the Nexus line of smartphones. They were officially announced on October 4, 2016 at the Made by Google event and released in the United States on October 20. On October 4, 2017, they were succeeded by the Pixel 2 and Pixel 2 XL. The Pixels have an aluminium chassis, with a glass panel on the rear, a USB-C connector, 3.5 mm headphone jack, and a 12.
Quantum computingA quantum computer is a computer that exploits quantum mechanical phenomena. At small scales, physical matter exhibits properties of both particles and waves, and quantum computing leverages this behavior, specifically quantum superposition and entanglement, using specialized hardware that supports the preparation and manipulation of quantum states. Classical physics cannot explain the operation of these quantum devices, and a scalable quantum computer could perform some calculations exponentially faster than any modern "classical" computer.
Avalanche photodiodeAn avalanche photodiode (APD) is a highly sensitive semiconductor photodiode detector that exploits the photoelectric effect to convert light into electricity. From a functional standpoint, they can be regarded as the semiconductor analog of photomultiplier tubes. The avalanche photodiode (APD) was invented by Japanese engineer Jun-ichi Nishizawa in 1952. However, study of avalanche breakdown, microplasma defects in silicon and germanium and the investigation of optical detection using p-n junctions predate this patent.
Auger electron spectroscopyAuger electron spectroscopy (AES; pronounced oʒe in French) is a common analytical technique used specifically in the study of surfaces and, more generally, in the area of materials science. It is a form of electron spectroscopy that relies on the Auger effect, based on the analysis of energetic electrons emitted from an excited atom after a series of internal relaxation events. The Auger effect was discovered independently by both Lise Meitner and Pierre Auger in the 1920s.
