Pooljuhtu

Pooljuhtu is a term derived from Estonian, meaning semiconductor. It refers to a material that has an electrical conductivity value between that of a conductor and an insulator. This unique property allows semiconductors to be used in electronic devices where their conductivity can be manipulated. The conductivity of a semiconductor can be changed by varying factors such as temperature, light, or the application of an electric field.

Commonly used semiconductor materials include silicon and germanium. These elements have a crystalline structure where their atoms are arranged in a regular, repeating pattern. The behavior of electrons within this structure determines the material's conductivity. In pure semiconductors, or intrinsic semiconductors, the number of charge carriers (electrons and holes) is limited.

To enhance their conductivity and control their electrical properties, semiconductors are often doped. Doping involves intentionally introducing impurities into the semiconductor crystal. This process creates extrinsic semiconductors. There are two types of extrinsic semiconductors: n-type and p-type. N-type semiconductors have an excess of electrons as charge carriers, while p-type semiconductors have an excess of holes (the absence of an electron).

The combination of n-type and p-type semiconductor materials forms a p-n junction, which is the fundamental building block of many electronic components such as diodes and transistors. These components are essential for modern electronics, enabling functions like amplification, switching, and signal processing. The study and application of semiconductors, known as semiconductor physics and engineering, are crucial for the development of all kinds of electronic devices.