Semiconductors characteristics
Answers
1. Electrical conductivity: Easy control on electrical conductivity by doping. By changing the dopant the same semiconductors can conduct both the electrons and holes. High level of doping can cause degeneracy in semiconductor and material can behave like a metal. If one forms an amorphous film of semiconductor, it will start behaving like insulator. These properties had led to several electronic devices such as diodes, transistors etc.
2. Optical properties: Semiconductors can have direct or indirect band gap. Direct band gap semiconductors can emit photon upon excitation by required wavelength. This property had led towards the development of lasers, LEDs and several other applications. Also the indirect band gap semiconductors can be made direct band gap by alloying.
3. Photo conductivity: A p-n junction, when illuminated, can produce a electron-hole pair. This electron-hole pair can be collected in at the electrodes, thereby, producing a current. This property has been used to develop solar cells and photo detectors.