Module 6 : PHYSICS OF SEMICONDUCTOR DEVICES
Lecture 31 : Electron in a Periodic Potential
  Example-1
Exercise 2
  Exercise 3
  Fermi Function
  At a finite temperature, the electron states are filled by a probability density function $ f(E)$ given by
 
$\displaystyle f(E) = \frac{1}{1+ e^{(E-E_F)/kT}}$
  where $ f(E)$ is the probability of a particular energy state $ E$ being occupied. Electrons and other particles which follow the above distribution function are called fermions . At $ T=0$, $ f(E)$ is a step function
 
$\displaystyle f(E)$ $\displaystyle =$ $\displaystyle 1\ \ {\rm for} \ \ E<E_F$
$\displaystyle =$ $\displaystyle 0\ \ {\rm otherwise}$
   
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