Module 6 : PHYSICS OF SEMICONDUCTOR DEVICES
Lecture 35 : Diffusion
$\displaystyle E_x = -\frac{d\phi}{dx} = \frac{1}{q}\frac{dE_F^i}{dx}\eqno(C)$
 
   
  Assume quasi-charge neutrality for which the concentration of holes is equal to the concentration of acceptors, $ p\simeq N_a$. Using one dimensional form of (B),
 
$\displaystyle \frac{dE_F^i}{dx} = \frac{kT}{p}\frac{dp}{dx} \simeq \frac{kT}{N_a}\frac{dN_a}{dx}$
 
5
7