Q. A $Ge$ specimen is doped with $Al$. The concentration of acceptor atoms is $- 10^{21}\ atoms/m^{3}$. Given that the intrinsic concentration of electron hole pairs is $\sim 10^{19}/m^{3}$, the concentration of electron in the specimen is
A) $10^{17}/m^{3}$
B) $10^{15}/m^{3}$
C) $10^{4}/m^{3}$
D) $10^{2}/m^{3}$
Explanation
(a) $n_{i}^{2} = n_{h}n_{e} \Rightarrow \left( 10^{19} \right)^{2} = 10^{21} \times n_{e} \Rightarrow n_{e} = 10^{17}/m^{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.