#importing modules
import math
from __future__ import division
#Variable declaration
T=300; #temperature(K)
mew_e=0.4; #electron mobility(m**2/Vs)
mew_h=0.2; #hole mobility(m**2/Vs)
Eg=0.7; #band gap(eV)
m0=9.1*10**-31; #mass of electron(kg)
mestar=0.55*m0; #electron effective mass(kg)
mhstar=0.37*m0; #hole effective mass(kg)
k=1.38*10**-23; #boltzmann constant
h=6.626*10**-34; #planck's constant
e=1.6*10**-19; #charge of electron(c)
#Calculation
a=(2*math.pi*k*T/(h**2))**(3/2);
Eg=Eg*e; #band gap(J)
b=-Eg/(k*T);
ni=2*a*((mhstar*mestar)**(3/4))*math.exp(b); #intrinsic concentration(per m**3)
sigma=ni*e*(mew_e+mew_h); #intrinsic conductivity(per ohm m)
rho=1/sigma; #intrinsic resistivity(ohm m)
#Result
print "intrinsic concentration is",round(ni/10**13,3),"*10**13 per m**3"
print "intrinsic conductivity is",round(sigma*10**6,3),"*10**-6 per ohm m"
print "intrinsic resistivity is",round(rho/10**6,2),"*10**6 ohm m"
#importing modules
import math
from __future__ import division
#Variable declaration
T=300; #temperature(K)
k=1.38*10**-23; #boltzmann constant
Nd=10**16; #donor concentration(per cm**3)
ni=1.45*10**10; #intrinsic concentration(per cm**3)
e=1.6*10**-19; #charge of electron(c)
#Calculation
Efd_Efi=k*T*math.log(Nd/ni); #fermi energy(J)
Efd_Efi=Efd_Efi/e; #fermi energy(eV)
#Result
print "fermi energy is",round(Efd_Efi,3),"eV"
#importing modules
import math
from __future__ import division
#Variable declaration
mew_e=1.35; #electron mobility(m**2/Vs)
mew_h=0.45; #hole mobility(m**2/Vs)
ni=1.45*10**13; #intrinsic concentration(per m**3)
NSi=5*10**28; #atomic concentration(per m**3)
e=1.6*10**-19; #charge of electron(c)
LbyA=1; #Si crystal(cm**3)
#Calculation
sigmai=ni*e*(mew_e+mew_h); #intrinsic conductivity(per ohm m)
rho=1/sigmai; #intrinsic resistivity(ohm m)
LbyA=LbyA*10**2; #Si crystal(m**3)
R1=rho*LbyA; #resistance(ohm)
Nd=NSi/10**9; #donor concentration(per m**3)
p=(ni**2)/Nd; #hole concentration(per m**3)
sigma=Nd*e*mew_e; #conductivity(per ohm m)
R2=(1/sigma)*100; #resistance(ohm)
#Result
print "resistance of 1cm**3 pure Si crystal is",round(R1/10**7,2),"*10**7 ohm"
print "resistance when crystal is doped with arsenic is",round(R2,2),"ohm"
#importing modules
import math
from __future__ import division
#Variable declaration
T=300; #temperature(K)
rho=2.12; #resistivity(ohm m)
mew_e=0.36; #electron mobility(m**2/Vs)
mew_h=0.17; #hole mobility(m**2/Vs)
mestar=0.5*m0; #electron effective mass(kg)
mhstar=0.37*m0; #hole effective mass(kg)
m0=9.1*10**-31; #mass of electron(kg)
k=1.38*10**-23; #boltzmann constant
h=6.626*10**-34; #planck's constant
e=1.6*10**-19; #charge of electron(c)
#Calculation
sigma=1/rho; #conductivity(per ohm m)
ni=sigma/(e*(mew_e+mew_h)); #intrinsic concentration(per m**3)
a=(2*math.pi*k*T/(h**2))**(3/2);
NC=2*a*(mestar**(3/2));
NV=2*a*(mhstar**(3/2));
b=(NC*NV)**(1/2);
Eg=2*k*T*math.log(b/ni); #energy gap of semiconductor(J)
Eg=Eg/e; #energy gap of semiconductor(eV)
#Result
print "energy gap of semiconductor is",round(Eg,3),"eV"
#importing modules
import math
from __future__ import division
#Variable declaration
e=1.6*10**-19; #charge of electron(c)
mew_e=0.39; #electron mobility(m**2/Vs)
mew_h=0.19; #hole mobility(m**2/Vs)
ni=2.4*10**19; #intrinsic concentration(per m**3)
#Calculation
sigmai=ni*e*(mew_e+mew_h); #conductivity of Ge(per Wm)
#Result
print "conductivity of Ge is",round(sigmai,3),"per Wm"
#importing modules
import math
from __future__ import division
#Variable declaration
EC_EF300=-0.3; #position of fermi level(eV)
T1=300; #temperature(K)
T2=330; #temperature(K)
k=1.38*10**-23; #boltzmann constant
e=1.6*10**-19; #charge of electron(c)
#Calculation
EC_EF330=-EC_EF300*T2/T1; #new position of fermi level(eV)
#Result
print "new position of fermi level is",EC_EF330,"eV"
#importing modules
import math
from __future__ import division
#Variable declaration
T1=20; #temperature(C)
T2=40; #temperature(C)
Eg=0.72; #energy gap(eV)
e=1.6*10**-19; #charge of electron(c)
k=1.38*10**-23; #boltzmann constant
sigmai20=2; #conductivity(per ohm m)
#Calculation
T1=T1+273; #temperature(K)
T2=T2+273; #temperature(K)
Eg=Eg*e; #energy gap(J)
a=(T2/T1)**(3/2);
b=Eg/(2*k);
c=(1/T1)-(1/T2);
ni40byni20=a*math.exp(b*c); #ratio of intrinsic concentration
sigmai40=sigmai20*ni40byni20; #conductivity at 40C(per ohm m)
#Result
print "conductivity at 40C is",round(sigmai40,3),"per ohm m"
#importing modules
import math
from __future__ import division
#Variable declaration
e=1.6*10**-19; #charge of electron(c)
k=1.38*10**-23; #boltzmann constant
T=300; #temperature(K)
m0=9.1*10**-31; #mass of electron(kg)
Eg=1.1; #energy gap(eV)
mestar=0.31*m0; #effective mass of electron(kg)
#Calculation
Eg=Eg*e; #energy gap(J)
a=(2*math.pi*k*T*mestar/(h**2))**(3/2);
b=-Eg/(2*k*T);
ni=2*a*math.exp(b); #intrinsic concentration(per m**3)
#Result
print "intrinsic concentration is",round(ni/10**15,4),"*10**15 per m**3"
#importing modules
import math
from __future__ import division
#Variable declaration
RH=-0.55*10**-10; #hall coefficient(m**3/As)
sigma=5.9*10**7; #conductivity(per ohm m)
#Calculation
mewd=-RH*sigma; #drift mobility(m**2/Vs)
#Result
print "drift mobility is",round(mewd*10**3,1),"*10**-3 m**2/Vs"
#importing modules
import math
from __future__ import division
#Variable declaration
sigma=5.9*10**7; #conductivity(per ohm m)
e=1.6*10**-19; #charge of electron(c)
mew=3.2*10**-3; #drift velocity(m**2/Vs)
N=6.022*10**23; #avagadro number
ne=8900*10**3; #number of free electrons per atom
w=63.5; #atomic weight of Cu(kg)
#Calculation
ni=sigma/(e*mew); #intrinsic concentration(per m**3)
n=N*ne/w; #concentration of free electrons(per m**3)
a=ni/n; #average number of electrons
#Result
print "intrinsic concentration is",round(ni/10**29,2),"*10**29 per m**3"
print "concentration of free electrons is",round(n/10**28,2),"*10**28 per m**3"
print "average number of electrons is",int(a)
#importing modules
import math
from __future__ import division
#Variable declaration
RH=3.66*10**-11; #hall coefficient(m**3/As)
sigma=112*10**7; #conductivity(per ohm m)
e=1.6*10**-19; #charge of electron(c)
#Calculation
n=3*math.pi/(8*RH*e); #concentration of electrons(per m**3)
mew_e=sigma/(n*e); #electron mobility(m**2/Vs)
#Result
print "concentration of electrons is",round(n/10**29,1),"*10**29 per m**3"
print "electron mobility is",round(mew_e,3),"m**2/Vs"
#importing modules
import math
from __future__ import division
#Variable declaration
i=50; #current(A)
B=1.5; #magnetic field(T)
n=8.4*10**28; #concentration of electrons(per m**3)
t=0.5; #thickness(cm)
w=2; #width of slab(cm)
e=1.6*10**-19; #charge of electron(c)
#Calculation
w=w*10**-2; #width of slab(m)
VH=B*i/(n*e*w); #hall voltage(V)
#Result
print "hall voltage is",round(VH*10**7,2),"*10**-7 V"