9: Physics of Semiconductor Devices

Example number 9.1, Page number 256

In [1]:
#importing modules
import math
from __future__ import division

#Variable declaration    
I0=0.3;     #current(micro A)
V=0.15;      #voltage(V)

#Calculations
I=I0*(math.exp(40*V)-1);      #value of current(micro A)

#Result
print "value of current is",round(I,2),"micro A"

value of current is 120.73 micro A

Example number 9.2, Page number 256

In [2]:
#importing modules
import math
from __future__ import division

#Variable declaration    
I=10*10**-3;     #current(A)
V=0.75;      #voltage(V)
T=300;    #temperature(K)
eta=2;

#Calculations
VT=T/11600;
I0=I*10**9/(math.exp(V/(eta*VT))-1);      #reverse saturation current(nA)

#Result
print "reverse saturation current is",round(I0,3),"nA"
print "answer in the book is wrong"

reverse saturation current is 5.043 nA
answer in the book is wrong

Example number 9.3, Page number 256

In [3]:
#importing modules
import math
from __future__ import division

#Variable declaration    
J=10**5;     #current density(amp/m**2)
T=300;    #temperature(K)
eta=1;
J0=250*10**-3;     #saturation current density(A/m**2)

#Calculations
VT=T/11600;
x=(J/J0)+1;
V=math.log(x)*VT;     #voltage applied(V)

#Result
print "voltage applied is",round(V,4),"V"

voltage applied is 0.3336 V

Example number 9.4, Page number 257

In [4]:
#importing modules
import math
from __future__ import division

#Variable declaration    
I0=4*10**-6;     #current(A)
T=273+25;    #temperature(K)
V=0.15;      #voltage(V)
eta=1;

#Calculations
VT=T/11600;
IF=I0*(math.exp(V/VT)-1);     #forward current(A)
IR=I0*(math.exp(-V/VT)-1);     #reverse current(A)
r=-IF/IR;       #rectification ratio

#Result
print "rectification ratio is",int(r)
print "answer in the book is wrong"

rectification ratio is 343
answer in the book is wrong

Example number 9.5, Page number 257

In [5]:
#importing modules
import math
from __future__ import division

#Variable declaration    
T=300;    #temperature(K)
eta=1;
I0=1;
I=-0.9*I0;     #saturation current density(A/m**2)

#Calculations
VT=T/11600;
x=(I/I0)+1;
V=math.log(x)*VT;     #voltage applied(V)

#Result
print "voltage applied is",round(V,2),"Volt"

voltage applied is -0.06 Volt