(3) Interaction of high energy photons with matter - LUTH

Semiconductors (1) – Band Structure
Semiconductors are solids similar to insulators, but with smaller bandgaps and with less impurities.
Their conductivity can be influenced with the application of electric fields or changes in temperature.
Semiconductor devices, electronic components made of semiconductor materials, are essential in
modern electrical devices, from computers to cellular phones to digital audio players.
A. Zech, Instrumentation in High Energy Astrophysics
from www.tpub.com
"Semiconductors' intrinsic electrical properties are very often permanently modified by introducing
impurities, in a process known as doping. Usually it is reasonable to approximate that each impurity atom
adds one electron or one "hole" that may flow freely. Upon the addition of a sufficiently large proportion
of dopants, semiconductors conduct electricity nearly as well as metals.
Depending on the kind of the impurity, a region of semiconductor can have more electrons or holes, and
then it is called N-type or P-type semiconductor, respectively. " (wikipedia)
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