Question
Explain the crystal structure for an intrinsic semiconductor with proper diagram.
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Answer
→Three-dimensional diamond-like crystal structure for semi-conductors like Carbon, Silicon, Germanium is shown in the figure. In all these atoms, there are four electrons (valence electrons) in the outer most orbit.
→In the crystal structure of Semiconductors, each atom is surrounded by four nearest neighbouring atoms, and each atom tends to share one of its four valence electrons with each of its four nearest neighbour atoms.
→And each atom also takes share of one electron from each such neighbour.
→These shared electron pairs are referred to as forming a covalent bond (or simply a valence bond.)
→The two shared electrons can be assumed to shuttle back and forth between associated atoms holding them together strongly.
→Here, as shown in fig., an atom can be taken at the centre of the tetrahedral and its four neighbouring atoms can be taken at the four vertices of the tetrahedral.
→By systematic and continuous three dimensional arrangement of such atoms, diamond like crystal structure is seen in carbon, $S i$ and $G e$ atoms.
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