Q. The energy band diagrams for three semiconductor samples of silicon are as shown. We can then assert that
A) Sample $X$ is undoped while samples $Y$ and $Z$ have been doped with a third group and a fifth group impurity respectively
B) Sample $X$ is undoped while both samples $Y$ and $Z$ have been doped with a fifth group impurity
C) Sample $X$ has been doped with equal amounts of third and fifth group impurities while samples $Y$ and $Z$ are undoped
D) Sample $X$ is undoped while samples $Y$ and $Z$ have been doped with a fifth group and a third group impurity respectively
Explanation
(d) In sample $x$ no impurity level seen, so it is undoped. In sample $y$ impurity energy level lies below the conduction bond so it is doped with fifth group impurity.
In sample $z$, impurity energy level lies above the valence band so it is doped with third group impurity
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.