Diffusion, drift & barrier voltage | Class 12 (India) | Physics | Khan Academy

Let's look at the different currents in a PN junction.
Learn the next topic here --www.khanacademy.org/science/i...
Class 12 Semiconductors: We cannot imagine our life without computers today. But what makes a computer tick? What's making this technology grow at such an exponential rate? It's all due to semiconductors. As unbelievable as that might sound, altering the properties of semiconductors allows us to build these computers. In this topic, we will explore the world of semiconductors. It's a journey from what semiconductors are all the way to creating building blocks of these computers.
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Created by Mahesh Shenoy

[@ethar899]

Sir, I have a PhD in physics and I've published more than 25 articles, 5 of them about P-N junction photodiodes, yet you truly and respectfully earn my respect.

[@aanchalshukla7022]

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[@hustling_dodo1354]

Spent 3 days on this chapter watching vdos from other channels. But I finally understood through his vdos

[@s.3421]

Guys I bet uh, u won't get a better video than this in the whole of the utube!! I wasted a lot of time, searching for a video where I could understand p n junction clearly... And then I found these videos where I understood it finally!!! Tqsm🙏🏻🙏🏻👏🏻👌🏻🥳🥳

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[@anjumanara1951]

I have always had this confusion about how the potential difference actually is created in that region and I never found an easy explanation to that before this video. So glad I found it!

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ka's semiconductors are worth to watch nd believe me, u probably wouldn't have any doubts...all the stuffs which are taught goes very smoothly into my mind..it was very helpful for last min revision..i love it..btw imma write my PHYSICS BOARD tomorrow🌚

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Same

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[@mkalaiyarasi]

Finally understood this concept....thank you soooo much😁

[@proudnepali8388]

Please help me, how can holes travel to N region , they are just the vacant place where electrons lack right ???

[@mahmoudbiomy8281]

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[@sainandhan1108]

Title says Class 12, Me understanding this after BTech for Gate. Best explanation of semiconductors in entire YT.

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[@proudnepali8388]

Please help me, how can holes travel to N region , they are just the vacant place where electrons lack right ???

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[@proudnepali8388]

Please help me, how can holes travel to N region , they are just the vacant place where electrons lack right ???

[@shauryaverma2705]

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[@advaitagautam3505]

OH MY GOD WHERE WAS THIS ALL THIS TIME???

[@sirilavanya6756]

Is holes really move from p type to n type during diffusion

[@786mrijaz]

If holes are not charges then why you have represented +1C charge from the p type region? Please reply

[@hazmanmohdnor]

can the 1 coulomb of charge moves from N to P type?

[@whatever3041]

a hole is a vacancy in the covalent bond, so I am not sure how you are kicking the +1C charge to the right? the movement of the hole is the movement of the bound electron in the covalent bond.

[@786mrijaz]

I also thought about the same thing

[@marvnet8898]

When an electron goes to P region for diffusion why all the other electrons in N region do not move a little bit to the right creating an electric field with the positive ions remaining in place?

[@mitchellmckay5448]

Nasty switches on that wall

[@SreenikethanI]

heheh

[@tanzistr]

Completed my class 12th and until today I didn't know why exactly was it called depletion region..

[@shahzadmuzaffar7094]

2:51 Sir why in the second condition still the current is in the same direction i.e. from P to N??

[@upendrauniyal9364]

If a hole can be formed in the depletion layer ( & cause drift current)can the reverse happen ie a recombination destroy drift current?

[@upendrauniyal9364]

Great video btw.

[@gold8780]

Drift current is not due to hole in depletion layer. Its bcuz of the electric field that arises in depletion layer And yes depletion layer gets destroyed - when you apply potential difference across it aka Forward biasing.

[@user-db3ez5vo8m]

I love you

[@vishnugovind4634]

coventia lcurrent here is same as the direction of electron

[@johnkarlosrodriguez8140]

Why is the diffusion of electron from N to the P will give a current with a direction of P to N? Same goes with the Drift current

[@reetichauhan355]

TristionMark ??? Because, remember your basics...current is always taken in the direction opposite to the motion of electrons

[@miscellaneousgaming8533]

Thats convention

[@proudnepali8388]

Please help me, how can holes travel to N region , they are just the vacant place where electrons lack right ???

[@RaviKumar-sw8dh]

What software you use to make these drawings

[@skyleonidas9270]

so, can you potentially shok someone with like a lot of these in series??

[@vaishaliVerma-ql1fo]

How to visualise a hole cancelling a negative charge As matter can neither be created nor be destroyed

[@ReactIonGlobal]

A hole itself is a theoretical construct, having no physical significance, question is how did you visualise that?😂😂 To answer your question, imagine that electron filling that hole.

[@safwanahmed8191]

U are doing great but in case of PN junction the net charge on P region and net charge on N region is not zero... Net charge on P is positive as it has become deficient of electrons (minority charge carriers) and same happens for N region where holes (minority charge carriers) have moved to P region.

[@safwanahmed8191]

I mean the P and N region seperately are not neutral.

[@yanaluvs]

Shut up I nearly cried out of happiness at 2 in the morning because of this dude

[@whitedaisy2263]

Why I didn't found it earlier 😭

[@alemayehumekonen7884]

But when the Ptve repels the t1 columb that come the B-ve Also Atttract It so the potential in the t1 columb must be constant

[@safwanlabeeb8029]

Help. Why does voltage increase with potential energy increase?

[@prashiksadar5717]

If their is inbuilt voltage in depletion region, then why we not use them as free voltage source.

[@KhanAcademyIndiaEnglish]

That's actually a really really good question. I remember seeing that question in Feynman's lectures as well. The short answer is, if you connect anything across the device you are adding more junctions. (The metal-semiconductor junction between the connecting wires & the P or N side terminals). There will be junction potentials across these as well. And it will all work out such that the net potential difference across the two metallic wires would all add up to be zero. :).

[@nafeesmuktadir3199]

Can someone please tell me,Why the potential energy of that +1C didn't go down after crossing the potential barrier

[@utkarshprithviraj2238]

as it moves toward the n-type region ...it goes against the electric field which means that is experiences a force toward the p-type region...hence its velocity continues to decrease till it reaches the n-type region...by conservation of energy this kinetic energy lost is manifested as potential energy of the 1 c charge hence the amount kinetic energy decrease the same amount potential energy increases

[@aditipatwa1848]

hey can anyone explain me how the electric field is taken as the same direction as the movemt of electrons

[@aditipatwa1848]

it would really be helpful for me pleasse help!!!

[@proudnepali8388]

Please I need help‼️‼️‼️ How can holes travel to N region please help me ?

[@ilaiyaraja5233]

Without external bias is there any drift?

[@KhanAcademyIndiaEnglish]

Yes. There is drift and diffusion. The two currents cancel out.

[@proudnepali8388]

@@KhanAcademyIndiaEnglish Please help me, how can holes travel to N region , they are just the vacant place where electrons lack right ??? 😭😭😭 I have become mad by not understanding this please help me😭😭😭

[@rickastleysmicrophone7544]

@@proudnepali8388 holes don't actually travel, yes. We just like to think of it that way. In reality, it's the electrons that are moving

[@mageshkailashkailash9791]

Bro you mentioned that holes are not particle but they consider to be the particle so that's why holes travelling through n junction??? Am I right

[@proudnepali8388]

Please help me, how can holes travel to N region , they are just the vacant place where electrons lack right ???

[@kotaslife667]

Why voltage of n side is higher than that of p side in the graph shown by you . Instead since left part of p type and right part of n type are neutral than their potential must remain the same ,but it does not ,how

[@akashgupta1307]

when the +1 charge crosses over to the n-type region from the depletion region, it gets no attractive pull in the neutral n-type. So it retains the same velocity with which it entered n-type. Hence it keeps moving with reduced but constant velocity, hence reduced but constant KE( than in P-type), hence more PE and hence more V (than in P-type).

[@proudnepali8388]

@@akashgupta1307 Please help me, how can holes travel to N region , they are just the vacant place where electrons lack right ???

[@akashgupta1307]

@@proudnepali8388 oh we imagine them to be moving charges. Suppose u have 3 plates 1,2,3. 2 & 3 have cakes on them & 1 is empty. The empty plate represents a hole & the 2 cakes represent an electron. Now u move cake on plate 2 to plate 1. After that u move cake on plate 3 to plate 2. Instead of talking about 2 different cakes to explain what happened, u can instead say the hole ( empty plate) moved from 1 to 2 , and then from 2 to 3. This is how we express the movement of holes. It's also easier as dealing with positive charge is more convenient. Hope you understood 🤝.

[@knowbettertodogreater4880]

But holes are in p junction not n junction.

[@aasthabharill7779]

3:13

[@malshimarasinghe6537]

Someone please give me an answer... are holes moving?

[@lilMartian78]

Holes are absence of electron

[@malshimarasinghe6537]

@@lilMartian78 Yeah I know that. I want to know that can a hole move alone?

[@JohnDoe-hl2qm]

Holes are not real thing so certainly the do not move, we say it is moving just to make things simple

[@malshimarasinghe6537]

@@JohnDoe-hl2qm thank you.

[@Shrreyy]

In reality the valence band electrons are moving, but it looks like that holes are moving

[@JesusTorres-yr9kw]

why in the f is the magnetic field pointing right to left.

[@himashridas8510]

It is not F it's E represent electric field and it's pointing right to left because it is a convention.

[@pujagupta7130]

Sir video hindi me baniye n

[@solaaar3]

you speak very fast.

[@miscellaneousgaming8533]

And I find him slow, whatchin him at 1.75×