We Can Figure This Out.org
Virtual Lab: How Semiconductors and Transistors Work
University of Virginia
             
 
© 2003-Present, John C. Bean
 
To make silicon conduct, we need to add impurity atoms such as phosphorus.

Phosphorus is immediately to the right of silicon in the periodic table which means that it has one more proton, neutron and electron (so the whole atom again has a net neutral charge).

The extra proton and neutron are added to the nucleus.

The extra electron creates a fifth electron cloud that can be used for bonding. Here we show that fifth cloud in bright blue.

 
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