We Can Figure This Out.org
Virtual Lab: Semiconductor Crystals
University of Virginia
© 2003-Present, John C. Bean
The simplest and strongest crystals are built from atoms having four valence electrons. Repelling one another, four electrons naturally arrange themselves into a tetrahedron, where each is separated by 109°. When these four electrons covalently bond with the electrons of similar atoms, they produce the structure seen here.

Atoms with four valence electrons lie in column IV of the periodic table. At the top of this column is carbon. When carbon forms this structure we call it diamond, the strongest material known to man. (to learn about alternate carbon "Nanostructures," click here).

Below carbon in column IV is silicon, which forms the same "diamond" type of crystal. Silicon crystals are used in that vast majority of modern microelectronic devices (to learn about "How Semiconductors & Transistors Work," click here).

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