PN Junction Depletion Width

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If you want to see more of these videos, or would like to say thanks for this one, the best way you can do that is by becoming a patron - see the link above :). And a huge thank you to all my existing patrons - you make these videos possible.
In this video, I discuss how to calculate the depletion width using only the built-in potential and doping concentrations.
This is part of my series on semiconductor physics (often called Electronics 1 at university). This is based on the book Semiconductor Physics and Devices by Donald Neamen, as well as the EECS 170A/174 courses taught at UC Irvine.
Hope you found this video helpful, please post in the comments below anything I can do to improve future videos, or suggestions you have for future videos.

[@pietrofumiani5337]

Maybe the charge value (q) is missing in the denominator of both final results for x_n and x_p. Thank You for your work is helping me very much regarding the WHY :D

[@JordanEdmundsEECS]

Ah! You’re right! That’s going to cause your answers to be off by 10 orders of magnitude, thanks for pointing that out.

[@Upgradezz]

Agreed

[@FernandoMinegv]

My college teacher has gone through pretty much every topic you explain in this series in barely a month, and he has done that explaining reaaaally poorly every topic. Sir, you're saving my butt and helping me learn useful and interesting stuff in the way, and although it's not being very easy (it's costing me plenty of hours to go through your videos) I reeaally appreciate your work here. Thank you so much for creating this videos and sharing (in a wonderful way btw) your knowledge.

[@JordanEdmundsEECS]

My pleasure:)

[@ThePradeepluke]

This is so helpful. You explain the Physics so nicely. Thank you so much

[@joxa6119]

I am from Malaysia and I prayed to God to bless you Dr. Edmund. Instead of paying universities' fees, I think I should use that money to pay you.

[@FNS_chn]

Thank you sir. I really appreciate your teaching .

[@rajeevkchauhan]

Sir, you are great. Doing good job for humanity. Keep it up!

[@thulasizwephetha8211]

truly, helping.......wish I found this early.........but its never too late THANKS

[@shifenghong5700]

Thank you sir! Those videos are really helpful for the understanding basic concepts of electronics.

[@sergiokpo434]

Thank you for the explanations. Now you are a saint

[@divyatejaswinivengada6368]

Beyond the depletion region at -wp and wn as the net charge is zero ,so in the electric field equation you can find the constant k by putting x= -wp or wn and then find the area under the electric field graph, which gives the Vbi that costs you less maths :)

[@TheCzaach]

Amazing viedo series sir ! Thank you.

[@RenegadeFury]

I accidentally took a semiconductor device theory class , a class I don't even need and probably shouldn't have taken since I had forgotten all my physics and only really focus on digital systems ;) your videos have been amazing at helping me get through the class!

[@JordanEdmundsEECS]

XD what a hilarious accident. Thank you!

[@RenegadeFury]

​@@JordanEdmundsEECS lmao, yeah it was a bit silly. I actually skipped the pre req too because I thought it was an undergrad class for some reason(it's not!). Needless to say it's been tough, but I'm actually liking the class, and you help explain things really clearly.

[@animeshsaurav7746]

thanx for such an awesome explanation sir.

[@priyanksharma4178]

Sir you are amazing! Lots of respect from India!

[@JordanEdmundsEECS]

Thanks :D

[@asmakhan8580]

Thanks for this video!

[@asmakhan8580]

Shouldn't there be a q in the denominator for xn and xp at the end?

[@ashlynnundlall]

Sir if possible put the word electronics in your channel name so you show up higher in the search results. Request 2. You have explained the theory to us very well but please can you do a few of the problem from each chapter in the Neaman book. In a seperate applications playlist. Hopefully KZbin allows you to go over the 1 hour mark. Thanks.

[@JordanEdmundsEECS]

Yes, that is a excellent suggestion, it is done, thank you. I can make a couple example videos, sure. I'll make them and post them in the next week or so.

[@sagarsaini1991]

good video

[@katieruland6851]

Is there a reason you chose to transform the coordinate system instead of using the boundaries at -xp and xn to define the equations?

[@TienNguyen-dt5sk]

The video sound is pretty good, beyond my imagination

[@JordanEdmundsEECS]

xD This was before I got a good mic. Thanks!

[@user-ge8hj9br6w]

why is the relation between Xn and Nd is so different from one equation to the other? isn't Vbi again a function of Na and Nd? 13:30

[@neutrspec]

Sir, why is the density of ion in P region equal to the density of the donor? Complete ionized? Is it an assumption or truth?

[@sender1496]

Why is epsilon_si used? Does the depletion-region act as a dielectric? Wouldn't that require free charges in the region?

[@JordanEdmundsEECS]

Great question, yes the depletion region does act as a dielectric. A dielectric actually doesn’t require free charges, it only requires *polarizable* species. For example, the electrons bound to an atom can be polarized, or stretched away from the nucleus (some of these are the bound electrons in the valence band).

[@sender1496]

@@JordanEdmundsEECS Ooh, yes that's true! Thanks a bunch :)

[@theamazingagares9043]

hello sir thank you very much for the explantations they were really usefull for me but i have a question though , i get it that the semiconducteur is neutral as a whole , the p side is neutral due to Na p and negative carriers, and the n side due to Nd p and negative carriers but the depletion region contains only Nd and Na due to the electirc field how can we assert that it is neutral ? or why it has to be neutral ? sorry for my bad english if there is any mistak.

[@JordanEdmundsEECS]

Excellent question, the depletion region *on either side* contains a net charge, but if you add up the charge on both sides you have no net charge. If you had a net charge, then you would have an electric field which moved charge around until there was no net charge.

[@cobra3359]

why r u calling the p side charges which are electrons as acceptors. Arent they donors?

[@OfficialAnarchyz]

A bit disappointed you didn't take the origin in the middle of the depletion zone, like in most literature

[@JordanEdmundsEECS]

Forgive me, I really hate negative numbers :p

[@idaahmad8294]

Tco