I love that you continue to reiterate and reincorporate the information until the vocabulary becomes synthesized, so that I can continue to build upon the story in my mind; thank you for your dedication to education on this material that requires focus to understand correctly.
"n" is not just intrinsic carrier concentration, it is concentration of electrons in the conduction band, which includes both intrinsic and extrinsic (from the ionized donors) carriers. At room temperature, total carrier concentration is approximately equal to the dopant concentration "N_d", which results in the equals 1 ratio. So to restate what is going on: At 0K, there are absolutely no donors in the conduction band, and there are absolutely no electron-hole pairs that have been created from the intrinsic material. Carrier concentration is absolutely zero. At low temperatures below 300K, some of the dopant material becomes ionized and electrons from those ionized donors are now present in the conduction band (because of the extremely small energy bandgap between the dopant material and the intrinsic material). There are effectively zero intrinsic carriers in the conduction band at this point still. Carrier concentration is slightly above zero. At room temperature 300K, the dopant material is effectively entirely ionized and almost all electrons from the ionized donors are now in the conduction band. Some intrinsic carriers are now present in the conduction band, but it is multiple orders of magnitude less than the extrinsic carriers. Carrier concentration is effectively the amount of ionized donors, hence the "extrinsic" region. At high temperatures, the dopant material is completely ionized, but now there are much more electron-hole pairs that have been created within the intrinsic material and this amount dominates the ionized donors. Carrier concentration is effectively the intrinsic concentration, hence the "intrinsic" region.
@@seinfan9 Thanks for the clarification! I wasn't notified on yr reply until I rewatched the video. I've always mistakenly thought the graph was n_i/N_D. My bad, thanks again!
I love that you continue to reiterate and reincorporate the information until the vocabulary becomes synthesized, so that I can continue to build upon the story in my mind; thank you for your dedication to education on this material that requires focus to understand correctly.
well said
Awesome course. Thanks.
It was mentioned that at room temperatures, intrinsic carrier concentration pales in comparison to the extrinsic carriers, which would mean that n/N_D
"n" is not just intrinsic carrier concentration, it is concentration of electrons in the conduction band, which includes both intrinsic and extrinsic (from the ionized donors) carriers. At room temperature, total carrier concentration is approximately equal to the dopant concentration "N_d", which results in the equals 1 ratio.
So to restate what is going on:
At 0K, there are absolutely no donors in the conduction band, and there are absolutely no electron-hole pairs that have been created from the intrinsic material. Carrier concentration is absolutely zero.
At low temperatures below 300K, some of the dopant material becomes ionized and electrons from those ionized donors are now present in the conduction band (because of the extremely small energy bandgap between the dopant material and the intrinsic material). There are effectively zero intrinsic carriers in the conduction band at this point still. Carrier concentration is slightly above zero.
At room temperature 300K, the dopant material is effectively entirely ionized and almost all electrons from the ionized donors are now in the conduction band. Some intrinsic carriers are now present in the conduction band, but it is multiple orders of magnitude less than the extrinsic carriers. Carrier concentration is effectively the amount of ionized donors, hence the "extrinsic" region.
At high temperatures, the dopant material is completely ionized, but now there are much more electron-hole pairs that have been created within the intrinsic material and this amount dominates the ionized donors. Carrier concentration is effectively the intrinsic concentration, hence the "intrinsic" region.
@@seinfan9 Thanks for the clarification! I wasn't notified on yr reply until I rewatched the video. I've always mistakenly thought the graph was n_i/N_D. My bad, thanks again!
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