Semiconductors

Thread Starter

aelec

Joined May 20, 2012
3
The formulae for the photocurrent in an illuminated photodetector is I=qAgop(Ln+Lp+W). Why is it W (depletion width) and not 2*W since both holes and electrons are optically genereted in the depletion region? Thanks :D
 

crutschow

Joined Mar 14, 2008
34,285
I think it's because the hole is created when the electron vacates a location in the semicondtor which creates the lack of an electron at that position (a hole). So each absorption of a photon creates one hole-electron pair.
 

Thread Starter

aelec

Joined May 20, 2012
3
Thank you for your answer, but let me make my question a little bit clearer. We have 1 electron and hole created, right? Now, both holes and electrons will move due to the electric field, so it a double contribution to the current. Why don't we consider 2*W?
 
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