A material with an electrical conductivity between that of a metal and that of an insulator. Semiconductors are used in electronic devices such as transistors and integrated circuits.

The term "semiconductor" reflects the fact that these materials have a conductivity that is in-between that of metals (which are good conductors) and insulators (which are poor conductors). This intermediate conductivity of semiconductors is what makes them useful in electronic devices.

Semiconductors are made of elements from groups 14, 15, and 16 of the periodic table. The most common semiconductors are silicon (Si), germanium (Ge), gallium arsenide (GaAs), and indium phosphide (InP). Silicon is the most widely used semiconductor material in electronic devices.

The electrical properties of semiconductors are strongly influenced by the presence of impurities. Impurities can either increase or decrease the conductivity of a semiconductor, depending on their type and concentration. This property of semiconductors is used to control the flow of current in electronic devices.

Semiconductors are used in a wide variety of electronic devices, including transistors, diodes, solar cells, and integrated circuits. Integrated circuits, or "chips", are the basic building blocks of computers and other electronic systems.