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Grade upto college level Physical Chemistry

Explain why does the conductivity of germanium crystals increase on doping with gallium.

Profile image of aditya kashyap
12 Years agoGrade upto college level
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1 Answer

Profile image of Gaurav
11 Years ago
Hello Student
Gallium is a trivalent element while germanium is tetravalent.
On doping germanium with gallium, some of the crystal sites are occupied by gallium atoms.
Three electrons of gallium are used for making bonds with germanium while the 4th electron of germanium remains unbounded and thus is free for movement and increases the conductivity of crystal.