# chapter02:Semiconductor Physics¶

## Example E1 - pg 35¶

In [1]:
#Calculate the conductivity and resistivity of germanium
#!/usr/bin/env/ python
#-*- coding: utf-8 -*-
q=1.6*10.**-19.#Coulomb        #charge of an electron
ni=2.5*10.**19.#per m**3        #concentration
un=0.36#m**2/Vs              #mobility of electron
up=0.17#m**2/Vs             #mobility of holes
con=q*ni*(un+up);           #conductivity
res=(1./con);                #resistivity
print '%s %.2f %s' %("The conductivty is =",con,'S/m');
print '%s %.2f %s' %("The resistivity is =",res,'ohm m');

The conductivty is = 2.12 S/m
The resistivity is = 0.47 ohm m


## Example E2 - pg 44¶

In [2]:
#Determine the conductivity of extrinsic semiconductor
#given
e=1.6*10.**-19.;#Coulomb        #charge of an electron
ni=1.5*10.**16.;#per m**3        #concentration
un=0.13;#m**2/Vs             #mobility of electron
up=0.05;#m**2/Vs            #mobility of holes
Si=5.*10.**28.;#per m**3        #atomic density in silicon
dop=(1./(2.*10.**8.));          #concentration of an antimony per silicon atoms
Nd=dop*Si;#per m**3       #donor concentraion
n=Nd;#per m**3           #free electron concentration
p=(ni**2/Nd);#per m **3   # hole concentration
con=e*(n*un+p*up);
print '%s %.1f %s' %("The conductivty is=",con, 'S/m');

The conductivty is= 5.2 S/m