A p - n junction possesses a depletion region that is 400 nm wide, wherein an electric field of 5 10^5 V m ⁻¹ exists. What is the minimum kinetic energy required for a conduction electron to diffuse from the n -side to the p -side?

Step-by-step solution

Width of the depletion region, d = 400 nm = 400 10⁻⁹ m Electric field in the depletion region, E = 5 10^5 V m ⁻¹ The potential barrier across the junction is given by V = E d V = (5 10^5) (400 10⁻⁹) = 0.2 V The minimum kinetic energy required for an electron to diffuse from the n -side to the p -side is equal to the energy required to overcome the potential barrier, which is K = eV K = e(0.2 V ) = 0.2 eV