# Chapter : 7 - Optoelectronic Devices¶

## Example : 7.6.1 - Page No : 7-16¶

In :
from __future__ import division
# Given data
O_V = 5;# output voltage in V
V_D = 1.5;#voltage drop in V
R = (O_V - V_D)/O_V;
R = R * 10**3;# in ohm
print "The resistance value = %0.f Ω" %R
print "As this is not standard value, use R=680 Ω which is a standard value"

The resistance value = 700 Ω
As this is not standard value, use R=680 Ω which is a standard value


## Example : 7.23.1 - Page No : 7-57¶

In :
from math import sqrt, log
# Given data
N_A = 7.5*10**24;# in atoms/m**3
N_D = 1.5*10**22;# in atoms/m**3
I_lembda = 12.5*10**-3;# in A/cm**2
D_e = 25*10**-4;# in m**2/s
D_h = 1*10**-3;# in m**2/s
Torque_eo = 500;# in ns
Torque_ho = 100;# in ns
n_i = 1.5*10**16;# in /m**3
e = 1.6*10**-19;
P_C = 12.5;# in mA/cm**2
L_e = sqrt(D_e*Torque_ho*10**-9);# in m
L_e = L_e * 10**6;# in µm
L_h = sqrt(D_h*Torque_ho*10**-9);# in m
L_h = L_h * 10**6;# in µm
J_s = e*((n_i)**2)*( (D_e/(L_e*10**-6*N_A)) + (D_h/(L_h*10**-6*N_D)) );# in A/m**2
J_s = J_s * 10**-4;# in A/cm**2
V_T = 26;# in mV
V_OC = V_T*log( 1+(I_lembda/J_s) );# in mV
V_OC = V_OC * 10**-3;# in V
print "Open circuit voltage = %0.3f V" %V_OC

Open circuit voltage = 0.522 V


## Example : 7.23.2 - Page No : 7-57¶

In :
from math import exp
# Given data
Phi_o = 1*10**21;# in m**-2s**-1
Alpha = 1*10**5;# in m**-1
W = 25;# in µm
W =W * 10**-6;# in m
e = 1.6*10**-19;# in C
G_L1 = Alpha*Phi_o;# in m**-3s**-1
G_L2 = Alpha*Phi_o*exp( (-Alpha*W) );# in m**-3s**-1
J_L = e*Phi_o*(1-exp(-Alpha*W));# in A/m**2
J_L = J_L * 10**-1;# in mA/cm**2
print "Photo current density = %0.2f mA/cm**2" %J_L

Photo current density = 14.69 mA/cm**2