How is it possible to have any intrinsic carrier concentration in a semiconductor?

[sarathgpk]

If the rate of generation=rate of recombination at equilibrium,how is it possible to have the presence of 1.5x 10^10 electrons and holes in an intrinsic semiconductor(Silicon)? Shouldn't they also get annihilated by recombination?(Since they were thermally generated, in equilibrium, there should be an equal and opposite process like recombination to nullify them.If they still exist, it means that generation rate somehow dominates recombination rate and the very existence of equilibrium is at stake.)

 

[jeffrey samuel]

can you tell us more about how they are created for that itself provides an answer to your question

the disturbance in the form of temperature rise causes them

at absolute zero there is perfect equilibrium and so there there is no probability of finding an electron or hole in a Si molecule structure

above the 0K mark the minimum energy is sufficient to keep the molecule in equilibrium and have electrons and holes

equilibrium is just a position or state where the system posses minimum energy at room temperature SAY 300K the minimum energy allows the presence of electrons and holes in intrinsic Si atoms

 

[Ratch]

sarath,

If the rate of generation=rate of recombination at equilibrium,how is it possible to have the presence of 1.5x 10^10 electrons and holes in an intrinsic semiconductor(Silicon)? Shouldn't they also get annihilated by recombination?(Since they were thermally generated, in equilibrium, there should be an equal and opposite process like recombination to nullify them.If they still exist, it means that generation rate somehow dominates recombination rate and the very existence of equilibrium is at stake.)

You propose some conditions, and then ask a contradictory question. If the R-G rate is at equilibrium, as you state, then how can the G rate be greater than the R rate if you just stated they are the same? If I own 12 electrons, and acquired one electron/sec and lose one electron/sec, why would I not have 12 electrons as long as my gain/loss rate stayed the same?

Ratch

 

[dick_freebird]

Every carrier generated needs some time to be annihilated.
In the meantime, it's contributing to N.

 

[jeffrey samuel]

Every carrier generated needs some time to be annihilated.
In the meantime, it's contributing to N.

exactly true thanks for it my man

hope you are bit more clear in this regards

 

[ecesoul]

Only RATE is same.
what already was there as free electrons remains there

 

[jeffrey samuel]

yeah rate of recombination is same since we have a ambient room temp of 300 K the amount of free electrons still remain above the fermi level at all time

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yeah rate of recombination is same since we have a ambient room temp of 300 K the amount of free electrons still remain above the fermi level at all time