Question

A group of 13 element if added in small amounts to $Ge$, then the type of semiconductor formed is:

• A. n-type semiconductor
• B. p-type semiconductor
• C. super semiconductor
• D. both $A$ and $B$

Answer 1

Answer: (B)

p-type semiconductor

A group 13 element (such as $B,Ga$ or $In$) is added in small amounts to $Si$ or $Ge$, then the type of semiconductor formed is p-type semiconductor. There will be positive holes in the lattice as $B$ is trivalent and $Ge$ is tetravalent.

Note: When a group 15 element (such as $P$ or $As$) is added in small amounts to $Si$ or $Ge$, then the type of semiconductor formed is n-type semiconductor. There will be extra electrons in the lattice as $P$ is pentavalent and $Ge$ is tetravalent.