carrier_concentration.py

# https://en.wikipedia.org/wiki/Charge_carrier_density
# https://www.pveducation.org/pvcdrom/pn-junctions/equilibrium-carrier-concentration
# http://www.ece.utep.edu/courses/ee3329/ee3329/Studyguide/ToC/Fundamentals/Carriers/concentrations.html

from __future__ importannotations


defcarrier_concentration(
electron_conc: float,
hole_conc: float,
intrinsic_conc: float,
) ->tuple:
"""
 This function can calculate any one of the three -
 1. Electron Concentration
 2, Hole Concentration
 3. Intrinsic Concentration
 given the other two.
 Examples -
 >>> carrier_concentration(electron_conc=25, hole_conc=100, intrinsic_conc=0)
 ('intrinsic_conc', 50.0)
 >>> carrier_concentration(electron_conc=0, hole_conc=1600, intrinsic_conc=200)
 ('electron_conc', 25.0)
 >>> carrier_concentration(electron_conc=1000, hole_conc=0, intrinsic_conc=1200)
 ('hole_conc', 1440.0)
 >>> carrier_concentration(electron_conc=1000, hole_conc=400, intrinsic_conc=1200)
 Traceback (most recent call last):
 ...
 ValueError: You cannot supply more or less than 2 values
 >>> carrier_concentration(electron_conc=-1000, hole_conc=0, intrinsic_conc=1200)
 Traceback (most recent call last):
 ...
 ValueError: Electron concentration cannot be negative in a semiconductor
 >>> carrier_concentration(electron_conc=0, hole_conc=-400, intrinsic_conc=1200)
 Traceback (most recent call last):
 ...
 ValueError: Hole concentration cannot be negative in a semiconductor
 >>> carrier_concentration(electron_conc=0, hole_conc=400, intrinsic_conc=-1200)
 Traceback (most recent call last):
 ...
 ValueError: Intrinsic concentration cannot be negative in a semiconductor
 """
if (electron_conc, hole_conc, intrinsic_conc).count(0) !=1:
raiseValueError("You cannot supply more or less than 2 values")
elifelectron_conc<0:
raiseValueError("Electron concentration cannot be negative in a semiconductor")
elifhole_conc<0:
raiseValueError("Hole concentration cannot be negative in a semiconductor")
elifintrinsic_conc<0:
raiseValueError(
"Intrinsic concentration cannot be negative in a semiconductor"
 )
elifelectron_conc==0:
return (
"electron_conc",
intrinsic_conc**2/hole_conc,
 )
elifhole_conc==0:
return (
"hole_conc",
intrinsic_conc**2/electron_conc,
 )
elifintrinsic_conc==0:
return (
"intrinsic_conc",
 (electron_conc*hole_conc) **0.5,
 )
else:
return (-1, -1)


if__name__=="__main__":
importdoctest

doctest.testmod()