Question

If we mix a pentavalent impurity in a crystal lattice of germanium, what type of semiconductor formation will occur?

• A. p-type
• B. n-type
• C. both A and B
• D. none

Answer 1

The correct option is B n-type

Germanium is a group 14 element that has four electrons in its valence shell. If we mix a pentavalent impurity in a crystal lattice of germanium, four out of five electrons are used in the formation of covalent bonds with the four neighbouring Ge atoms.

The extra fifth electron becomes delocalised and this increases the conductivity of the germanium. Therefore, n type semiconductor formation takes place.

Hence, option B is the correct option.