J

Junctions

In electronics, the interface between two different types of materials within diodes, transistors, and other semiconductor devices.

K

There are no definitions yet for words beginning with K

L

lab-on-a-chip devices

Miniaturized analytical systems that integrate a chemical laboratory on a chip. Lab-on-a-chip technology enables portable devices for point-of-care (or on-site) medical diagnostics and environmental monitoring.

Langmuir-Blodgett (LB) films

Ultrathin films (monolayers and isolated molecular layers) created by nanofabrication. An LB-film can consist of a single layer or many, up to a depth of several visible-light wavelengths. The term Langmuir-Blodgett comes from the names of a research scientist and his assistant, Irving Langmuir and Katherine Blodgett, who discovered unique properties of thin films in the early 1900s. Such films exhibit various electrochemical and photochemical properties. This has led some researchers to pursue LB-films as a possible structure for integrated circuits (ICs). Ultimately, it might be possible to construct an LB-film memory chip in which each data bit is represented by a single molecule. Complex switching networks might be fabricated onto multilayer LB-films chips.

Lattice

In crystallography, a regular periodic arrangement of atoms in three-dimensional space.

LED (light-emitting diode)

A semiconductor device that converts electrical energy into electromagnetic radiation. The LED emits light of a particular frequency (hence a particular color) depending on the physical characteristics of the semiconductor used. See electroluminescence.

Liposome

A type of nanoparticle made from fat molecules surrounding a core of water. Liposomes were the first nanoparticles used to create unique therapeutic agents.

Liquid phase separation

A method of extracting one liquid from another, generally through the use of solvents.

Lithography

The process of imprinting patterns on materials. Derived from Greek, the term lithography means literally "writing on stone.” Nanolithography refers to etching, writing, or printing at the microscopic level, where the dimensions of characters are on the order of nanometers (units of 10 -9 meter, or millionths of a millimeter).

Luminescence

Cool light emitted by sources as a result of the movement of electrons from more energetic states to less energetic states. There are many types of luminescence. Chemiluminescence is produced by certain chemical reactions. Electroluminescence is produced by electric discharges, which may appear when silk or fur is stroked or when adhesive surfaces are separated. Triboluminescence is produced by rubbing or crushing crystals.

M

Macromolecule

A very large molecule composed of hundreds or thousands of atoms.

Magnetism

The force of attraction or repulsion between various substances, especially those made of iron and certain other metals. Magnetism is the result of the motion of electrons in the atoms.

Mass spectrometer

A device used to identify the kinds of molecules present in a given substance: the molecules are ionized and passed through an electromagnetic field. The way in which they are deflected is indicative of their mass and identity.

Microcontact printing

A technique that uses a silicone stamp to deposit molecules on surfaces in patterns with microscale features.

Microfluidic device

A device that has one or more channels with at least one dimension less than 1 mm. Common fluids used in microfluidic devices include whole blood samples, bacterial cell suspensions, protein or antibody solutions and various buffers. The small amounts of samples needed and relative inexpensiveness of microfluidic devices make them attractive for biomedical research and creating clinically useful technologies. One of the long term goals in the field of microfluidics is to create integrated, portable clinical diagnostic devices for home and bedside use, thereby eliminating time consuming laboratory analysis procedures.

Microfluidics

A multidisciplinary field that studies the behavior of fluids at volumes thousands of times smaller than a drop. Microfluidic components form the basis of “lab-on-a-chip” devices capable of performing several different functions. Microfluidics is critical in the development of gene chip and protein chip technology.

Micromachining

The use of standard semiconductor technologies along with special processes to fabricate miniature mechanical devices and components on silicon and other materials. See micromolding.

Micromolding

An method of fabricating microsystems using tiny molds to cast materials. Micromolding serves as an alternative to micromachining. See micromachining.

MOCVD (Metal-Organic Chemical Vapor Deposition)

A technique for growing thin layers of compound semiconductors in which metal-organic compounds are decomposed near the surface of a heated substrate wafer.

Molecular beam epitaxy

Method used to grow layers of materials of atomic-scale thickness on surfaces.

Molecular imprinting

A process by which functional monomers are allowed to self-assemble around a template molecule and locked into place. The template molecule is then removed, leaving behind a cavity that is complementary in shape and functionality as the template molecule, which will bind molecules identical to the template.

Monomer

A small molecule that may become chemically bonded to other monomers to form a polymer; from Greek mono "one" and meros "part".