Question

Let $n_p$ and $n_e$ be the numbers of holes and conduction electrons in an extrinsic semiconductor, then

• A. $n_p>n_e$
• B. $n_p=n_e$
• C. $n_p<n_e$
• D. $n_p\ne n_e$

Answer 1

Answer: (D)

$n_p\ne n_e$

As extrinsic semiconductor is obtained by doping pure semiconductor like Si, Ge either with electron rich or electron deficient impurity like As, P, Al, B, etc. and thus the electrons in conduction band is not equal to number of holes in the valance band.

So $n_p\ne n_e$