Semiconductors are solids. Their electrical conductivity lies between that of insulators and that of electrical conductors such as copper – but it can be changed in a targeted way.
WHAT DISTINGUISHES SEMICONDUCTORS
Semiconductors do not conduct electricity at temperatures close to the absolute zero of –273.15 degrees Celsius. If the temperature rises, their conductivity increases – unlike with metals.
In contrast to metals, not only negatively charged electrons migrate in semiconductors. The electrons leave behind positive voids, so-called holes, which also move.
The properties such as the conductivity of a semiconductor can be specifically influenced by heat and light, but also by incorporating foreign atoms (doping).
Semiconductors can be made either from one element (particularly from silicon), from a combination of different substances such as gallium arsenide, and from organic, that is, carbonaceous materials.
IN USE EVERYWHERE
Semiconductors paved the way for the triumph of microelectronics. They are in computer chips, smartphones, television sets, cars, solar cells and lasers. They are also interesting for quantum computers.
WHAT IS JÜLICH DOING?
Researchers are dealing with fundamental questions of semiconductor physics, with materials and technologies. They are developing devices and components for nanoelectronics, laser technology, photovoltaics and quantum computing.
Illustrations: Diane Köhne