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Electronics Engineering
Elements and Compounds
Atoms and Atomic Structure
Particle Physics

Is the current in intrinsic semiconductos du to fre electrons or valence electrons and what is the diff between them?


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May 06, 2008 5:50AM

Well intrinsic semiconductor is semiconductor crystal with no impurities in it. In intrinsic semiconductor the electrons in valence band(valence electrons) gain energy(due to thermal enegry) and break free into conduction band(means it become free electrons). As this electron breaks free, a vacancy is created in place of it. It is called as a hole. This hole has a positive charge. So current in semiconductor is due to flow of this free electrons and holes. But this current is very small in magnitude. The difference between free electrons and valenece electrons is that valence electrons are often bonded to other atoms in crystal. But free electrons can freely move throughout the crystal.