Q. An n-type silicon sample with Nd=10^16cm-3 is steadily illuminated such that g'=10^21cm-s^-1. If tn0=tp0=10^-6s, calculate the position of the quasi-Fermi levels for electrons and holes with respect to the intrinsic level (assume that ni=1.5x10^10cm^-3).© BrainMass Inc. brainmass.com October 24, 2018, 5:25 pm ad1c9bdddf
Please see attached for solution.
The excess carrier concentration due to steady light illumination is:
dn = dp = gtn (no trapping) ...
The solution clearly explains how to obtain the quasi Fermi level given the data in the question using relevant theory.
Separation of Quasi and Intrinsic Fermi Levels and Conductivity
An undoped Si sample is optically excited at 300K such that Gop=10^19 ehp/cm^3s and taun=taup=1 microseconds.
(a) What is the separation of the quasi Fermi levels (Efn-Efp)?
(b) Where is Efn and Efp with respect to the intrinsic Fermi level Ei?
(c) What is the change in conductivity due to excess carriers?
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