# 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