Anyone who has studied, even superficially, some thermodynamics has encountered the word adiabatic very early. This is because adiabatic processes are extremely useful to understand the basics of the field. An adiabatic process is any process that occurs without heat (or matter) entering or leaving a system. In general, an adiabatic change involves a fall […]
Japan is known to be one of the world technological leaders. Having to import many of the raw materials and fuels its industry needs, it has been basic research and the development of technologies based on it what have transformed Japan in a window into the future. An important part of that future is based […]
Usually, the concept of exciton is linked to that of nonmetallic crystal: an electron-hole pair in a crystal that is bound in a manner analogous to the electron and proton of a hydrogen atom. It behaves like an atomic excitation (hence the name) that passes from atom to another and may be long-lived. Exciton behaviour […]
As the search for renewable energy sources has intensified, the discovery of efficient and cheap technologies for exploiting the energy from the sunlight has emerged as a key challenge. Higher efficiency plays an increasingly important role in making competitive solar cell designs as the price of silicon continues to drop. At present, the actual silicon […]
Lithium-ion batteries are widely used in portable electronic devices and electric vehicles since their introduction by Sony in 1991. Safety is an important concern since about two billion cells are produced every year but with a one-in-200,000 failure rate. Excessive temperature variations and high temperatures over the melting point of the metallic lithium can cause […]
We are all familiar with the equation of ideal gases: PV = nRT. To deduce this equation, an ideal model of the gas is considered. In this model, gases are composed of particles so tiny compared to the volume of the gas that they can be considered zero-volume points in space, and there are no […]
Chemistry • Condensed matter • Materials • Physics • Quantum physics
Minimizing losses in any kind of electronic device is always important, but it is paramount in nanoelectronics. Still, most of the phenomena that lead to inefficiencies in the operation of these nanodevices are poorly understood. Consider the case of quantum dots. A quantum dot is a nanometric crystalline structure of semiconductor materials. In a quantum […]
When two superconducting materials are separated by a very thin (less than 10-8 m or 10 nanometers) layer of an insulating material at very low temperature some peculiar electrical effects can be detected called Josephson effects. If normal conducting metals are separated by such a barrier in that conditions it is possible for a small […]
We are all familiar with rust. Rust is an iron oxide, usually red, formed by the reaction of iron and oxygen in the presence of water or air moisture, and it is a clear sign of metal corrosion by oxidation. Oxidation is a ubiquitous phenomenon that proceeds via the electrochemical interaction of ambient oxygen molecules […]
The current in a semiconductor consists of two parts: the negatively charged electrons in the conduction band and the positively charged holes in the valence band. Although the number of electrons in the conduction band is equal to the number of holes in the valence band, the two contributions to the current are in general […]