In a p-n junction, a potential barrier of 250 meV exists across the junction. A hole with a kinetic energy of 300 meV approaches the junction. Find the kinetic energy of the hole when it crosses the junction if the hole approached the junction

(a) from the p-side and


(b) from the n-side


Potential barrier, d = 250 meV

Initially the kinetic energy of the hole = 300 meV


(a) When the hole approaches the junction from p-side, junction will act like forward biasing.


Therefore, the kinetic energy of the hole will decrease.


Final kinetic energy of the hole = (300-250) meV


= 50 meV


(b) When the hole approaches the junction from n-side, junction will act like reverse biasing.


Therefore, the kinetic energy of the hole in this case will increase.


Final kinetic energy of the hole = (300+250) meV


= 550 meV


1