In [3]:

```
#Variables
m = 9.107 * 10**-31 #Mass of electron (in kilogram)
E = 2.1 #Energy associated (in electon-volt)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
#Calculation
E = E * e #Energy associated (in Joules)
v = (2 * E / m)**0.5 #Velocity of electron (in meter per second)
#Result
print "Velocity of electron at fermi level is ",round(v,2)," m/s."
#Slight variation due to higher precision.
```

In [4]:

```
#Variables
J = 2.4 * 10**6 #Current Density (in Ampere per meter-square)
n = 5.0 * 10**28 #Electron density
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
#Calculation
v = J / (e * n) #Drift velocity (in meter per second)
#Result
print "Drift velocity is ",v," m/s."
```

In [5]:

```
#Variables
n = 10**24 #Electron density
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
v = 1.5 * 10**-2 #Drift velocity (in meter per second)
A = 1.0 * 10**-4 #Area of cross-section (in meter-square)
#Calculation
I = e * n * v * A #Current (in Ampere)
#Result
print "Magnitude of current is ",I," A."
```

In [4]:

```
#Variables
p = 0.039 #Resistivity of doped material (in ohm-centimeter)
e = 1.602 * 10**-19 #Charge on electron (in Coulomb)
ue = 3600.0 #Carrier mobility (in centimeter-square per volt-second)
ni = 2.5 * 10**13 #Intrinsic concentration (in per cubic-centimeter)
#Calculation
sign = 1/p #Conductivity (in per ohm-centimeter)
ND = sign /(e * ue) #Concentration of donor atoms (in per cubic-centimeter)
n = ND #Concentration of electron (per cubic-centimeter)
p = ni**2 / n #Concentration of hole (per cubic-centimeter)
#Result
print "Concentration of electrons is ",n," /cm**3.\nConcentration of holes is ",p," \cm**3."
#Slight variation due to higher precision.
```

In [9]:

```
#Variables
N = 5.0 * 10**22 #Number of silicon atoms (per cubic-centimeter)
N1 = 10**-6 #Donor impurity
ni = 1.45 * 10**10 #Intrinsic concentration (in per cubic-centimeter)
l = 0.5 #Length (in centimeter)
A = (50.0 * 10**-4)**2 #Area of cross-section (in centimeter-square)
ue = 1300.0 #Mobility of electron (in )
#Calculation
ND = 5 * 10**16 #Donor concentration (in per cubic-centimeter)
n = ND #Mobile electron concentration (in per cubic-centimeter)
p = ni**2 / ND #Hole concentration (in centimeter-square per volt-second)
sig = n * e * ue #Conductivity of doped silicon sample (in per ohm-cetimeter)
p1 = 1/sig #Resistivity (in ohm-centimeter)
R = p1 * l / A #Resistance (in ohm)
#Result
print "Resulting donor concentration is ",ND," /cm**3.\nResulting mobile electron concentration is ",n," /cm**3.\nResulting hole concentration is ",p," /cm**3."
print "Conductivity of doped silicon sample is ",sig," (ohm-cm)**-1.\nResistivity is ",p1," ohm-cm and Resistance is ",R," ohm."
```

In [10]:

```
#Variables
ni = 1.4 * 10**18 #intrinsic concentration (in per cubic-centimeter)
ND = 1.4 * 10**24 #Donor concentration (in per cubic-centimeter)
n = ND #Concentration of electrons (in per cubic-centimeter)
#Calculation
p = ni**2 / ND #Concentration of holes (in per cubic-centime)
ratio = n / p #Ratio of electron to hole concentration
#Result
print "Ratio of electron to hole concentration is ",ratio,"."
```

In [12]:

```
#Variables
Ef = 5.5 #Fermi energy (in electron-volt)
ue = 7.04 * 10**-3 #Mobility of electrons (in meter-square per volt-second)
n = 5.8 * 10**28 #Concentration of electrons (in per cubic-centimeter)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
m = 9.1 * 10**-31 #Mass of electron (in kilogram)
#Calculation
tau = ue * m / e #Relaxation time (in seconds)
p = 1 / (n * e * ue) #Resistivity (in ohm-meter)
vf = (2 * Ef * e / m)**0.5 #Velocity of electron with fermi energy (in meter per second)
#Result
print "Relaxation time is ",tau," s.\nResistivity of conductor is ",p,"ohm-meter.\nVelocity of electrons with fermi energy is ",vf," m/s."
#Slight variation due to higher precision.
```

In [14]:

```
#Variables
ni = 2.5 * 10**13 #Intrinsic concentration (in per cubic-centimeter)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
uh = 1800.0 #Mobility of holes (in per cubic-centimeter)
ue = 3800.0 #Mobility of electrons (in per cubic-centimeter)
#Calculation
sigi = ni * e * (ue + uh) #Conductivity (in per ohm-centimeter)
pi = 1/sigi #Resistivity (in ohm-centimeter)
#Result
print "Conductivity is ",sigi," (ohm-cm)**-1.\nResistivity is ",round(pi,2)," ohm-cm."
```

In [1]:

```
#Variables
pi = 0.47 #intrinsic resistivity (in ohm-meter)
ue = 0.39 #Electron mobility (in meter-square per volt-second)
uh = 0.19 #Hole mobility (in meter-square per volt-second)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
E = 10**4 #Electric field (in volt per meter)
#Calculation
sigi = 1 / pi #Conductivity (in per ohm-meter)
ni = sigi/(e * (ue + uh)) #Intrinsic concentration (in per cubic-meter)
vn = ue * E #Drift velocity of electrons (in meter per second)
vh = uh * E #Drift velocity of holes (in meter per second)
#Result
print "Density of electrons is ",ni," /m**3.\nDrift velocity of electrons is ",vn," m/s.\nDrift velocity of holes is ",vh," m/s."
```

In [2]:

```
#Variables
ni = 1.5 * 10**10 #Intrinsic concentration (in per cubic-centimeter)
uh = 450.0 #mobility of holes (in centimeter-square per volt-second)
ue = 1300.0 #mobility of electrons (in centimeter-square per volt-second)
NA = 10**18 #Doping level (in per cubic-centimeter)
#Calculation
sigi = ni * e * (ue + uh) #Conductivity of silicon (in per ohm-centimeter)
sigp = e * NA * uh #COnductivity of P-type silicon (in per ohm-centimeter)
#Result
print "Conductivity of intrinsic silicon is ",sigi," /ohm-cm.\nConductivity of P type silicon is ",sigp," ohm-cm."
```

In [5]:

```
#Variables
ni = 2.5 * 10**13 #Intrinsic concentration (in per cubic-centimeter)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
uh = 1800.0 #mobility of holes (in centimeter-square per volt-second)
ue = 3800.0 #mobility of electrons (in centimeter-square per volt-second)
ND = 4.41 * 10**22 * 10**-7 #Number of Germanium atoms (in per cubic-centimeter)
#Calculation
sigi = ni * e * (uh + ue) #Intrinsic concentration (in per ohm-centimeter)
n = ND #Concentration of electrons (in per cubic-centimeter)
p = ni**2 / ND #Concentration of holes (in per cubic-centimeter)
sign = e * ND * ue #Conductivity of N-type germanium semiconductor (in per ohm-meter)
#Result
print "Conductivity of intrinsic semiconductor is ",sigi," /ohm-cm.\nConductivity of N-type semiconductor is ",round(sign,2)," /ohm-cm."
```

In [11]:

```
#Variables
V = 10.0 #Voltage (in volts)
l = 0.025 #Length (in meter)
uh = 0.18 #mobility of holes (in meter-square per volt-second)
ue = 0.38 #mobility of electrons (in meter-square per volt-second)
ni = 2.5 * 10**19 #Intrinsic concentration (in per cubic-imeter)
a = 4.0 * 1.5 *10**-6 #Area of cross-section (in meter-square)
#Calculation
E = V / l #Electric field (in volt per meter)
ve = ue * E #Drift velocity of electrons (in meter per second)
vh = uh * E #Drift velocity of holes (in meter per second)
sigi = ni * e * (ue + uh) #Conductivity of intrinsic semiconductor (in per ohm-meter)
I = sigi * E * a #Total current (in Ampere)
#Result
print "Electron drift velocity is ",ve," m/s.\nHoles drift velocity is ",vh," m/s.\nIntrinsic conductivity of Ge is ",sigi," /ohm-m.\nTotal current is ",I * 10**3," mA."
```

In [13]:

```
#Variables
ni = 2.5 * 10**13 #Intrinsic concentration (in per cubic-centimeter)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
uh = 1700.0 #mobility of holes (in centimeter-square per volt-second)
ue = 3600.0 #mobility of electrons (in centimeter-square per volt-second)
k = 1.38 * 10**-23 #Boltzmann constant (in Joule per kelvin)
T = 300.0 #Temperature (in kelvin)
#Calculation
De = ue * k * T / e #Diffusion constant of electrons (in centimeter-square per second)
Dh = uh * k * T / e #Diffusion constant of holes (in centimeter-square per second)
#Result
print "Diffusion constant of electron is ",round(De)," cm**2/s.\nDiffusion constant of holes is ",Dh," cm**2/s."
#Slight variation in Dh due to higher precision.
```

In [15]:

```
#Variables
p = 9.0 * 10**3 #Resistivity (in ohm-meter)
RH = 3.6 * 10**-4 #Hall coefficient (in cubic-meter per Coulomb)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
#Calculation
sig = 1/p #Conductivity (in per ohm-meter)
P = 1/ RH #Charge density (in Coulomb per cubic meter)
n = P / e #Density of charge carriers (in per cubic-meter)
u = sig * RH #Mobility (in meter-square per volt-second)
#Result
print "Mobility of charge carriers is ",u," m**2/V-s.\nDensity of charge carriers is ",n," /m**3."
```

In [18]:

```
#Variables
E = 100.0 #Electric field (in volt per meter)
RH = 0.0145 #Hall coefficient (in cubic-meter per Coulomb)
un = 0.36 #Mobility of electrons (in meter-square per volt-second)
#Calculation
n = 1/(e * RH) #Concentration (in per cubic-meter)
J = n * e * un * E #Current density (in Ampere per cubic-meter)
#Result
print "The current density in the specimen is ",round(J,2)," A/m**2"
#Slight variation due to higher precision.
```

In [20]:

```
#Variables
p = 9.0 * 10**-3 #Resistivity (in ohm-meter)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
u = 0.03 #Mobility of carrier ion (in meter-square per volt-second)
#Calculation
sig = 1/p #Conductivity (in per ohm-meter)
RH = u / sig #Hall coefficient (in cubic-meter per Coulomb)
#Result
print "Hall coefficient is ",RH," m**3/C."
```

In [6]:

```
#Variables
p = 9.0 * 10**3 #Resistivity (in ohm-meter)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
n = 2.05 * 10**22 #Charge carrier density (in per cubic-meter)
#Calculation
RH = 1/(n * e) #Hall coefficient (in cubic-meter per Coulomb)
#Result
print "Hall coefficient is ",round(RH,7)," m**3/C."
#Slight variation due to higher precision.
```

In [26]:

```
#Variables
Ex = 5.0 * 10**2 #Applied Electric field (in volt per meter)
ue = 3800.0 * 10**-4 #Mobility of electron (in meter-square per volt-second)
Bz = 0.1 #Magnetic flux density (in Weber per meter-square)
d = 4.0 * 10**-3 #width (in meter)
#Calculation
v = ue * Ex #Drift velocity (in meter per second)
VH = Bz * v * d #Hall voltage (in volts)
#Result
print "Hall voltage is ",VH * 10**3," mV."
```

In [30]:

```
#Variables
p = 200.0 * 10 #Bar resistivity (in ohm-meter)
VH = 50.0 * 10**-3 #Hall voltage (in volts)
BZ = 0.1 #Magnetic flux density (in Weber per meter-square)
w = 3.0 * 10**-3 #width (in meter)
d = w #length (in meter)
I = 10.0 * 10**-6 #Current (in Ampere)
#Calculation
RH = VH * w / (BZ * I) #Hall coefficient (in cubic-meter per Coulomb)
uh = RH / p #Mobility of holes (in meter-square per volt-second)
#Result
print "Mobility of holes is ",uh," m**2/V-s."
```

In [33]:

```
#Variables
ND = 1.0 * 10**21 #Concentration of donor atoms (in per cubic-meter)
BZ = 0.2 #Magnetic field density (in Tesla)
J = 600.0 #Current density (in Ampere per meter-square)
n = ND #Concentration of electrons (in per cubic-meter)
d = 4.0 * 10**-3 #Length (in meter)
e = 1.6 * 10**-19 #Charge on electron (in Coulomb)
#Calculation
VH = BZ * J * d / (n * e) #Hall voltage (in volts)
#Result
print "Hall voltage is ",VH * 10**3," mV."
```

In [37]:

```
#Variables
T = 300.0 #Temperature (in kelvin)
Ec_Ef = 0.3 #Energy level (in electron-volt)
T1 = 273 + 55 #New temperature (in kelvin)
#Calculation
logencbyND = Ec_Ef/T #Value of loge(nc / ND)
Ec_Ef1 = T1 * logencbyND #New position of Fermi level (in electron-volt)
#Result
print "New position of Fermi level is ",Ec_Ef1," eV"
#Unit in the book should be eV instead of V.
```

In [41]:

```
import math
#Variables
ND = NA = 8.0 * 10**14 #Concentration (in per cubic-meter)
ni = 2.0 * 10**13 #Intrinsic concentration (in per cubic-meter)
k = 8.61 * 10**-5 #Boltzmann constant (in electron-volt per kelvin)
T = 300.0 #Temperature (in kelvin)
#Calculation
Vo = k * T * math.log(ND * NA/ni**2)
#Result
print "Potential barrier is ",round(Vo,2)," eV."
#Unit in the book should be eV instead of V.
```

In [44]:

```
#Variables
ID1 = 2.0 * 10**-3 #Diode current1 (in Ampere)
VD1 = 0.5 #Diode voltage1 (in volts)
ID2 = 20.0 * 10**-3 #Diode current2 (in Ampere)
VD2 = 0.8 #Diode voltage2 (in volts)
ID3 = -1.0 * 10**-6 #Diode current3 (in Ampere)
VD3 = -10.0 #Diode voltage3 (in volts)
#Calculation
R1 = VD1 / ID1 #Resistance1 (in ohm)
R2 = VD2 / ID2 #Resistance2 (in ohm)
R3 = VD3 / ID3 #Resistance3 (in ohm)
#Result
print "R1 is ",R1," ohm.\nR2 is ",R2," ohm.\nR3 is ",R3 * 10**-6," Mega-ohm."
```

In [9]:

```
import math
#Variables
k = 8.61 * 10**-5 #Boltzmann constant (in electron-volt per kelvin)
T = 300.0 #Temperature (in kelvin)
EG = 0.72 #Energy band gap (in electron-volt)
#Calculation
EF = 1.0/2 * EG #Fermi level (in electron-volt)
ncbyn = 1/(1 + math.exp((EG-EF)/(k*T))) #Ratio
#Result
print "Fraction of the total number of electrons in the conduction band at 300 K is ",round(ncbyn*pow(10,7),2),"e-7 ."
```

In [1]:

```
import math
#Variables
Ao = 4.83 * 10**21 #Constant
T = 300.0 #Temperature (in kelvin)
EG = 1.1 #Energy level (in electron-volt)
kT = 0.026 #Product of k and T (in electron-volt)
ND = 5.0 * 10**15 #Donor concentration (in per cubic-meter)
NA = 2.0 * 10**16 #Acceptor concentration (in per cubic-meter)
#Calculation
ni = Ao * T**1.5 * math.exp(-EG/(2*kT)) #Intrinsic concentration (in per cubic-meter)
h = ni**2 / NA #Hole concentration (in per cubic-meter)
n = ni**2 / ND #Electron concentration (in per cubic-meter)
#Result
print "Since electron concentration",round(n*10**-16,2),"e+16 is more than hole concentration ",round(h*10**-16,2),"e+16 .Therefore , Si is of n-type."
#Slight variations due to higher precision.
```