# Chapter16:Semiconductors¶

## Ex16.1:pg-315¶

In [27]:
#Example 16.1 : concentration

#given data :
e=1.602*10**-19;# Coulomb
sigma_i=5*10**-4;# in ohm/m
mu_n=0.14;# in m**2/V-sec
mu_p=0.05;# in m**2/V-sec
n_i=sigma_i/(e*(mu_n+mu_p));
print round(n_i*10**6,-20),"= the concentration,n_i(/cm**3)  "

1.64e+22 = the concentration,n_i(/cm**3)


## Ex16.2:pg-315¶

In [28]:
#Example 16.2 : intrinsic carrier

#given data :
e=1.602*10**-19; # Coulomb
p_i=2*10**-4;# in ohm-m
mu_n=6;# in m**2/V-sec
mu_p=0.2;# in m**2/V-sec
n_i=1/(e*(mu_n+mu_p)*p_i);
print round(n_i,-19),"= the intrinsic carrier,n_i(/m**3) "

5.03e+21 = the intrinsic carrier,n_i(/m**3)


## Ex16.3:pg-315¶

In [1]:
#Example 16.3 : neglect the intrinsic conductivity

#given data :
e=1.6*10**-19; # Coulomb
sigma=10**-12;# in mhos/m
mu_n=0.18;# in m**2/V-sec
n=sigma/(e*mu_n);
N=n; # amount of n type impurity
print "{:.2e}".format(N),"in(/m**3)  "
# The answer is slightly different in textbook due to approximation

3.47e+07 in(/m**3)


## Ex16.4:pg-315¶

In [30]:
#Example 16.4 : number of electron carriers

#given data :
e=1.6*10**-19; # Coulomb
p=20*10**-2;# in ohm-m
mu_n=100*10**-4;# in m**2/V-sec
n=1/(e*mu_n*p);
print round(n,-19),"= number of electrons carrier,n(/m**3)  "

3.12e+21 = number of electrons carrier,n(/m**3)


## Ex16.5:pg-316¶

In [32]:
#Example 16.5 : concentration of impurity
import math
e=1.6*10**-19;# Coulomb
l=10;#in mm
d=1;#in mm
r=100;#in ohms
up=0.19;#mobilty of electrons in V-sec
a=(math.pi*((d*10**-3)**2))/4;#area in m**2
p=((r*a))/(l*10**-3);#resistivity in Ohm-cm
n=((1/(p*e*up)));#concentration in per m**3
print round(n,-19),"is impurity concentration is in per m**3"

4.19e+21 is impurity concentration is in per m**3


## Ex16.6:pg-316¶

In [39]:
#Example 16.6 : intrinsic carrier density

#given data :

e=1.602*10**-19; # in coulomb
p=3000.0;# in ohm/m
sigma=1/p;# in ohm/m
mu_n=0.14;# in m**2/V-sec
mu_p=0.05;# in m**2/V-sec
n_i=sigma/(e*(mu_n+mu_p));
print round(n_i,-13),"is the concentration,n_i(/m**3) "

1.095e+16 is the concentration,n_i(/m**3)


## Ex16.7:pg-317¶

In [4]:
#Example 16.7 : conductivity

#given data :
e=1.602*10**-19; # in coulomb
n_i=5.021*10**15; # in m**-3
mu_n=0.48;# in m**2/V-sec
mu_p=0.013;# in m**2/V-sec
sigma=n_i*(e*(mu_n+mu_p));
print "{:.3e}".format(sigma),"= the conductivity,sigma(ohm**-1 m**-1)  "

3.966e-04 = the conductivity,sigma(ohm**-1 m**-1)