In [1]:

```
from __future__ import division
e_c=550## number of electron collected
p=800## number of photon incident
n=e_c/p## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=1.3*10**-6# wavelength in m
R=(n*e*y)/(h*c)## responsivity in A/W
print "The responsivity =%0.2f Amp/Watt"%( R)
```

In [2]:

```
from __future__ import division
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=0.85*10**-6# wavelength in m
R=0.274## responsivity in A/W
n=(R*h*c)/(e*y)## quantum efficiency
n1=n*100## % of quantum efficiency
print "The quantum efficiency =%0.2f %%"%( n1)
```

In [3]:

```
from __future__ import division
e_c=1## number of electron collected
p=3## number of photon incident
n=e_c/p## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=0.8*10**-6# wavelength in m
Eg=(h*c)/y## band gap energy in J
R=(n*e*y)/(h*c)## responsivity in A/W
Po=10**-7## in W
Ip=R*Po## output photo current
print "The quantum efficiency =%0.2f %%"%( n*100)#
print "\n band gap energy =%0.2f*10**-20 J"%( Eg*10**20)#
print "\n The output photo current =%0.2f nA"%( Ip*10**9)
```

In [4]:

```
from __future__ import division
n=0.50## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=0.85*10**-6# wavelength in m
R=(n*e*y)/(h*c)## responsivity in A/W
Ip=10**-6## mean photo current
Po=Ip/R## received optical power in W
f=c/y#
re=(n*Po)/(h*f)#
rp=re/n## number of received photons
print "The responsivity =%0.2f A/W"%( R)#
print "\n The received optical power =%0.2f uW"%( Po*10**6)#
print "\n The number of received photons =%0.2f*10**13 photons/sec"%( rp/10**13)
```

In [5]:

```
from __future__ import division
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
Eg=1.43## in eV
Eg1=Eg*1.602*10**-19## in J
y=(h*c)/Eg1## cut off wavelength in m
print "The cut off wavelength =%0.2f um"%( y*10**6)
```

In [6]:

```
from math import pi
from __future__ import division
vd=2.5*10**4## carrier velocity in m/s
w=30*10**-6## width in m
Bm=vd/(2*pi*w)#
Tm=1/Bm## max response time in sec
Tm1=Tm*10**9## max response time in ns
print "The max response time =%0.2f ns"%( Tm1)
```

In [7]:

```
from math import ceil,pi
from __future__ import division
n=0.65## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=0.85*10**-6# wavelength in m
R=(n*e*y)/(h*c)## responsivity in A/W
Po=0.35*10**-6## in W
Ip=R*Po## output photo current
I=9*10**-6## output current in A
M=I/Ip## multiplication factor
M1=ceil(M)#
print "The multiplication factor =%d"%( M1)
```

In [1]:

```
from __future__ import division
n=0.50## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
Eg=1.5*10**-19## in J
y=(h*c)/Eg## cut off wavelength in m
f=c/y#
R=(n*e)/(h*f)## responsivity in A/W
Ip=2.7*10**-6## photo current in A
Po=Ip/R## incident optical power in W
Po1=Po*10**6## incident optical power in uW
print "The cut off wavelength =%0.2f um"%( y*10**6)#
print "\n The responsivity =%0.2f A/W "%( R)#
print "\n The incident optical power =%0.2f uW"%( Po1)
```

In [2]:

```
from __future__ import division
n=0.15## quantum efficiency
e=1.6*10**-19## charge
h=6.63*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=0.85*10**-6## cut off wavelength in m
f=c/y## frequency in Hz
R=(n*e)/(h*f)## responsivity in A/W
print "The responsivity =%0.2f A/W "%( R)
```

In [3]:

```
from __future__ import division
Iph=75*10**-6## output photocurrent in A
y=0.85## operating wavelength in um
Pi=750*10**-6## incident optical power in uW
R=Iph/Pi## responsivity in A/W
n=1.24*R/y## external quantum efficiency
n1=n*100## percentage of external quantum efficiency
print "The responsivity =%0.2f A/W "%( R)#
print "\n The external quantum efficiency =%0.2f%% "%( n1)
```

In [4]:

```
from __future__ import division
Vs=10**5## saturation in m/s
W=7*10**-6## depletion layer width in m
tr=W/Vs## transit time in sec
print "The transit time =%0.2f ps"%( tr*10**12)
```

In [6]:

```
from __future__ import division
Vs=3*10**4## saturation in m/s
W=25*10**-6## depletion layer width in m
tr=W/Vs## transit time in sec
f=0.35/tr## max 3 dB bandwidth Hz
f1=f/10**6## max 3 dB bandwidth Hz
print "The max 3 dB bandwidth =%d MHz"%( f1)#
print "\n The answer is wrong in the textbook"
```

In [7]:

```
from __future__ import division
Vs=3*10**4## saturation in m/s
W=25*10**-6## depletion layer width in m
E=10.5*10**-11## in F/m
RL=15*10**6## load resister in ohm
A=0.25*10**-6## area in m**2
tr=W/Vs## transit time in sec
Cj=E*A/W## junction capacitance in F
t=RL*Cj## time constant in sec
print "The transit time =%0.2f ns"%( tr*10**9)#
print "\n The junction capacitance =%0.2f pF"%( Cj*10**12)#
print "\n The time constant =%0.2f us"%( t*10**6)
```

In [8]:

```
from __future__ import division
Eg1=1.12## band gap for Si in eV
Eg2=0.667## band gap for Ge in eV
y_si=1.24/Eg1## cut off wavelength for Si in um
y_he=1.24/Eg2## cut off wavelength for Ge in um
print "The cut off wavelength for Si =%0.2f um"%( y_si)#
print "\n The cut off wavelength for Ge =%0.2f um"%( y_he)
```

In [9]:

```
from __future__ import division
n=0.50## quantum efficiency
e=1.6*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=0.9*10**-6# wavelength in m
R=(n*e*y)/(h*c)## responsivity in A/W
Ip=10**-6## mean photo current
Po=Ip/R## received optical power in W
f=c/y#
re=(n*Po)/(h*f)#
rp=re/n## number of received photons
print "The responsivity =%0.2f A/W"%( R)#
print "\n The received optical power =%0.2f uW"%( Po*10**6)#
print "\n The number of received photons =%0.2f*10**13 photons/sec"%( rp/10**13)
```

In [10]:

```
from __future__ import division
R=0.40## Responsivity in A/W
m=100*10**-6## incident flux in W/m-m
A=2## area in m-m
Po=m*A## incident power in W
Ip=R*Po## photon current in A
print "The photon current =%d uA"%( Ip*10**6)
```

In [11]:

```
from __future__ import division
n=0.65## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
Eg=1.5*10**-19## in J
y=(h*c)/Eg## cut off wavelength in m
f=c/y#
R=(n*e)/(h*f)## responsivity in A/W
Ip=2.5*10**-6## photo current in A
Po=Ip/R## incident optical power in W
Po1=Po*10**6## incident optical power in uW
print "The cut off wavelength =%0.2f um"%( y*10**6)#
print "\n The responsivity =%0.2f A/W "%( R)#
print "\n The incident optical power =%0.2f uW"%( Po1)
```

In [12]:

```
from __future__ import division
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
Eg=1.43## in eV
Eg1=Eg*1.602*10**-19## in J
y=(h*c)/Eg1## cut off wavelength in m
print "The cut off wavelength =%0.2f um"%( y*10**6)
```

In [13]:

```
from __future__ import division
n=0.45## quantum efficiency
h=6.62*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=1.2*10**-6## cut off wavelength in m
Ic=20*10**-6## collector current in A
Po=120*10**-6## incident optical power in W
e=1.602*10**-19## charge
Go=(h*c*Ic)/(y*Po*e)## optical gain
h_e=Go/n## common emitter gain
print "The optical gain =%0.2f"%( Go)#
print "\n The common emitter gain =%0.2f"%( h_e)
```

In [14]:

```
from __future__ import division
n=0.5## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=1.3*10**-6# wavelength in m
R=(n*e*y)/(h*c)## responsivity in A/W
Po=0.4*10**-6## in W
Ip=R*Po## output photo current
I=8*10**-6## output current in A
M=I/Ip## multiplication factor
print "The multiplication factor =%d"%( M)
```

In [15]:

```
from __future__ import division
n=0.85## quantum efficiency
e=1.6*10**-19## charge
h=6.625*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=0.9*10**-6# wavelength in m
R=(n*e*y)/(h*c)## responsivity in A/W
Po=0.6*10**-6## in W
Ip=R*Po## output photo current
I=10*10**-6## output current in A
M=I/Ip## multiplication factor
print "The multiplication factor =%d"%( M)
```

In [16]:

```
from __future__ import division
e_c=1.2*10**11## number of electron collected
p=2*10**11## number of photon incident
n=e_c/p## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
E=1.5*10**-19## energy in J
y=(h*c)/E# wavelength in m
R=(n*e*y)/(h*c)## responsivity in A/W
Ip=2.6*10**-6## photocurrent in A
Po=Ip/R## incident optical power in W
print "The quantum efficiency =%d %%"%( n*100)#
print "\n The wavelength =%0.2f um"%( y*10**6)#
print "\n The responsivity =%0.2f Amp/Watt"%( R)#
print "\n The incident optical power =%0.2f uW"%( Po*10**6)
```

In [17]:

```
from __future__ import division
n=0.40## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=1.35*10**-6# wavelength in m
R=(n*e*y)/(h*c)## responsivity in A/W
Po=0.2*10**-6## in W
Ip=R*Po## output photo current
I=4.9*10**-6## output current in A
M=I/Ip## multiplication factor
print "The multiplication factor =%d"%( M)
```

In [18]:

```
from __future__ import division
n=0.55## quantum efficiency
e=1.6*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=0.85*10**-6# wavelength in m
R=(n*e*y)/(h*c)## responsivity in A/W
Ip=2*10**-6## mean photo current
Po=Ip/R## received optical power in W
re=(n*Po*y)/(h*c)## number of received photons
print "The responsivity =%0.2f A/W"%( R)#
print "\n The received optical power =%0.2f uW"%( Po*10**6)#
print "\n The number of received photons =%0.2f*10**13 photons/sec"%( re/10**13)
```

In [19]:

```
from __future__ import division
h=6.625*10**-34## plank constant
c=3*10**8## speed of light in m/s
n=1## quantum efficiency
e=1.602*10**-19## charge
E=1.3*10**-19## energy in J
y=(h*c)/E## wavelength in m
M=18## multiplication factor
rp=10**13## no. of photon per sec
Po=rp*E## output power in w
Ip=(n*Po*e)/E## output photocurrent in A
I=M*Ip## photocurrent in A
print "The wavelength =%0.2f um"%( y*10**6)#
print "\n The output power =%0.2f uW"%( Po*10**6)#
print "\n The photocurrent =%0.2f uA"%( I*10**6)
```

In [20]:

```
from __future__ import division
e_c=2*10**10## number of electron collected
p=5*10**10## number of photon incident
n=e_c/p## quantum efficiency
e=1.602*10**-19## charge
h=6.626*10**-34## plank constant
c=3*10**8## speed of light in m/s
y=0.85*10**-6## wavelength in m
y1=0.85## wavelength in um
Eg=(h*c)/y## bandgap energy in J
Eg1=1.24/y1## bandgap energy in terms of eV
Po=10*10**-6## incident power in W
Ip=(n*e*Po)/Eg## mean output photocurrent in A
print "The quantum efficiency =%d %%"%( n*100)#
print "\n The bandgap energy =%0.2f*10**-19 J"%( Eg*10**19)#
print "\n The bandgap energy =%0.2f eV"%( Eg1)#
print "\n The mean output photocurrent =%0.2f uA"%( Ip*10**6)
```