Steady state excess carrier - Semiconductor

[kidsasd987]

Please check the following questions.

Steady state of semiconductor w.r.t excess carrier.

1. If we shine photons on semiconductor and then turn the light off, semiconductor is not under the steady state condition. (it is under transient state since excess carrier concentration is decreasing)

2. If we shine photons for a long time, then it will reach steady state. (generation=recombination)

 

[berkeman]

Please check the following questions.

Steady state of semiconductor w.r.t excess carrier.

1. If we shine photons on semiconductor and then turn the light off, semiconductor is not under the steady state condition. (it is under transient state since excess carrier concentration is decreasing)

2. If we shine photons for a long time, then it will reach steady state. (generation=recombination)

Technically, those are statements, not questions... Is this for schoolwork?

 

[kidsasd987]

Technically, those are statements, not questions... Is this for schoolwork?

Sorry. I forgot to add a sentence.

"Please confirm if these statements are true, and if not please tell me why."

 

[berkeman]

What is the context of these questions?

 

[kidsasd987]

What is the context of these questions?

please check this video from 1:06:41 to 1:07:48.

So, the whole ppt is about excess carrier genearation and continuity equation.
But if we find the solution for 1st order ode, delta n(t) is a exponential function and its derivative is also exponential.

if delta n(t) is at steady state, its time derivative must be 0. so, I assume that the first statement is true.

 

[kidsasd987]

2nd satement is a bit confusing.

(2.9.9)

(2.9.10)

(2.9.11)

(2.9.12)

generation rate - recombination = 0 (difussion ->recombination)
therefore, delta n and delta p are constant values, hence steady state.

* is the steady state concentration delta n (or delta p) dependent on the intensity and frequency of light that we shine onto semiconductor?