Extrinsic semiconductors N-type | Class 12 (India) | Physics | Khan Academy

[@gvcallen]

Why is this only on Khan Academy India? Should be on the normal Khan Academy for more people to see! Excellent content

[@amalsrivastava6853]

well maybe because in most first world countries this is taught in colleges while in India we learn this in school

[@maroon3353]

@@amalsrivastava6853 that's true... I'm in class 12th so kinda can figure out 😅

[@hibudy]

@@amalsrivastava6853 that's your misconception

[@hibudy]

Because khan academy from the very beginning wants to focus on India to spread free quality education (you can see several interview with indian medias out there) to the masses. And sal also has an indian root so that might played some sort of role.

[@maroon3353]

@@hibudy I agree that ...

[@nguyenvanhongphuc1729]

I get goosebumps listening to these amazing explanations!!! Love it!!!

[@udaypatel9596]

This channel is just awesome. It deserves the best. Really, the teachers here at KHAN ACADEMY are super cool and make our concepts crystal clear and much easy. Not like that at my school. Really hat's off. Salute from me.

[@_rafiaahmad]

I AM SO THANKFUL TO THIS MAN 🙏 He explains wonders 💯

[@91-ritikjain36]

I luv your teaching and you clear all my concept

[@suhailakhtar1707]

extremely useful

[@16meashiqka96]

Your explanation , voice and colourful graphical representation is very nice..

[@alankritsharma6678]

wont the group 15 and group 13 elements that are used to dope the semiconductor have there own conduction bands separate form the si / gr atom's conduction bands?

[@KhanAcademyIndiaEnglish]

Excellent question. Since the doping level is extremely low. We can assume the doped atoms are isolated. And isolated atoms would just have discrete energy levels & not bands.

[@charumeow8382]

@@KhanAcademyIndiaEnglish thanks 🙏

[@kartikkumar3432]

thank you very much.. this is great

[@chamodya.t.k]

Thank you soo much I 've always had a doubt abt this N type and P type being neutral but it never occured to me that the atom we add becomes an ion!🥴 Thank you soo much again for teaching the whole thing🤩

[@pankajrai6441]

I do agree as none made clear this concept!

[@balabhakti9106]

These videos are brilliant. I work for intel in components research. Enjoying your content !. Thank you Mahesh Shenoy

[@UmmUkashah]

Excellent!

[@oliveoliver4990]

Excellent explanation

[@preethipara8028]

Excellent 🤗

[@zarina7459]

Thank you so much. I helped me alot

[@votelearn1244]

you are genius!

[@vivekgupta3692]

Sir In Previous Video You Said That When An Electron Jump From Valance Band To Conduction Band It Leaves A Vacant Space Which We Call Hole. By Same Logic In Doner Level Also When Electron Will Jump From Doner Level To Conduction Band Then It Should Also Leave A Hole In Doner Level. In That Case In Extrinsic Conductor Also The Number Of Holes And Electron Should Be Equal. But You Are Saying That In Extrinsic Semiconductor The Number Of Electrons In Conduction Band Is Greater Then Number Of Holes.....How Please Explain.??

[@KhanAcademyIndiaEnglish]

Great question! Holes are left behind when an electron jumps from covalent bonds (in the Valence band) to the conduction band. The donated electrons were NOT covalently bonded! So, they don't leave behind a hole (in the donor level).

[@vivekgupta3692]

@@KhanAcademyIndiaEnglish Thank you so much sir

[@sohiniachary4684]

The explanation is very good🙂☺☺

[@komalhayat417]

this is called ''the best''

[@g.k.karunya6310]

Yes bro

[@aronhighgrove4100]

The name extrinsic means that something external was added, i.e., the material was doped.

[@manyasingla922]

Its really helpful 😊. Thanks for clearing all the doubts

[@darshantl18]

Hello Sir why phosphorus having energy level nearer to the conduction band???

[@darshantl18]

Why donor level decreases for group 16 and 17 elements???

[@karunsingh5506]

It's an awsm explanation

[@gunajothisekar5053]

Instead of doing this why can't we just use a conductor

[@penumalasunitha14]

Sir, please clarify my doubt. Firstly, thankyou so much for the amazing best video. My doubt is that...here, in ntype semiconductor, no of electrons are greater than no. Of. Holes. ACCORDING to, recombination, the electrons should fall into holes. Because, there are so many electrons. Then finally, there should be no holes in the ntype semiconductor. Please kindly clarify my doubt sir, please

[@vinitmehta1707]

Yes it does happen and along with that the generation process also keeps happening since it is a spontaneous process and moreover the rate of recombination is same as the rate of generation so always the no of electrons is higher than the number of holes

[@p.kavitha2136]

In case of semiconductor the absence of electron at particular place in an atom is called hole . But y can't we say the same concept in case of a conductor because here also electrons move from valence shell

[@p.harika]

Even I have same question but no one there to clear.

[@gurwinderkaur7104]

@@p.harika If i explain you this quantum mechanically to conduct electricity an electron needs to be in superposition of two different energies so in valence band when a hole is created an nearby electron in valence band could be excited by thermal agitation and it could be in superposition of two energy states at the same time. It is like the same thing that electron can have probability of being found at two different places at the same time.

[@p.harika]

@@gurwinderkaur7104 thanks a ton for your explanation I was wondering it from long time

[@gurwinderkaur7104]

@@p.harika your welcome:-)

[@dhanushas9248]

Sir, you had mentioned in previous video that no two electrons have same energy level,then how all phosphorus Valence electron occupy same energy sir

[@caesarxi1303]

I don't know, but I think they only can't have the same energy level when their atoms are "connected". All those electrons would be from separated phosphorus atoms which are far from each other, each having its own *exclusive* energy level at that height.

[@anaresh9742]

Sir ,Can we use carbon atoms as a semi conductor?

[@reetichauhan355]

Naresh Yadav no, because the electrons are so tightly bound to nucleus ( remember c is small in size, in the first period ) if you add that as dopant, you’d require a lot of energy to excite those electrons , which is ultimately not beneficial

[@reetichauhan355]

@@arshad4695 That is an exception due to its layered structure, there is one loosely bound electron that gives conductivity

[@LarryLovestein23]

When the phosphorous becomes positive, and the electrons move to the conduction band, do the holes left move to the valence band or no?

[@raskkas6201]

when we have only silicon atom at room temperature no. of electron is equal to no. of holes. as generation process still recombination happens the ne=nh right. after doping, if phosphorous donate one free electron also we get one hole so how this N-type get holes minority and electrons majority, pls explain.

[@KhanAcademyIndiaEnglish]

Good question, this is explained in detail in another video named "majority & minority carriers"

[@sktfaker489]

Dude phosphorus usually after donating e- becomes +vely charged. it does not create holes usually. :)

[@runzit2007]

Excellent 👌👌👌👌

[@melissa_abbott]

If I consider a part of the crystal (like in the diagram), and consider a row, wouldn't there be multiple conduction bands (and valence bands) for each row? How does that explain the concept of 'free' electrons or the fact that in P-type semiconductors, the acceptor level of a Boron atom is at a lower energy level than the conduction band?

[@abdullahbabar5466]

Since silicon has its own conduction band phosphorus should also has it own conduction band it's should move there after excitation . Please explain it will be obliged Regards

[@atanunath]

A conduction band is more like a shared band, a band that belongs to all the atoms, that's why the electrons there conduct. So, even if valance bands are different for Si and P, the conduction bands are one single overlapped band. One can imagine the valance band as due to an inner orbital that doesn't touch with an inner orbital of the other atoms, while a conduction band corresponds to the outer orbital that touches and overlaps with the outer orbitals of other atoms, therefore becoming more like one large orbital spanning the whole crystal.

[@melissa_abbott]

​@@atanunathSo a valence band is exclusive to every single atom, while the conduction band is common for all the atoms?

[@muaiadsiddig3327]

Much Respect 💛

[@roshankumar2555]

Could you please explain why donor level of sulphur is close to the valance band?

[@Fatima-o4m5f]

5:59 why did he draw alot of electrons on the energy level of phosphorus? he said that there should only be 2 electrons per energy level

[@alankritsharma6678]

why not use group 16 elements or group 12 elements

[@KhanAcademyIndiaEnglish]

Great question. For doping to make sense the energy level of the extra electron (for pentavalent) / the vacancy (for trivalent) need to be close to the conduction band (so electrons can easily jump) / valence band (so the electrons from valence band can jump creating holes). This will only be true for group 15 & 13. Keep asking these great questions :)

[@catharperfect7036]

Shockingly good explanation sir. I would like to subscribe to your magazine.

[@roshankumar2555]

Could you please explain why donor level of sulphur is close to the valance band as he described in the video?

[@dr.reenajain4900]

Which software is he using

[@aakashSky-0]

exactly? did you find out?

[@joannewelch545]

It looks like some sort of Autodesk software (maybe Sketchbook?)

[@maheedharsai9433]

Paint 3D on windows 10

[@jhansi1012]

good explanation sir

[@s.h.1991]

Thanks 🤩

[@girishdeshpande6843]

11:01 What math are we talking about? Can someone pls explain...

[@siriram66]

Don't think cleverly .......

[@R.Srividhya2024]

Sir you already told that no two electrons can be identical ,then why you have drawn many electrons in the same energy level of donor atom?

[@olaayman1900]

thank you

[@rustamdhankhar4962]

Why the donor level is shifting downwards while using S and Cl respectively

[@natasharani20]

I think it is due to the decreasing tendency to donate the electrons.(remember electronegativity increases in a period as we go from left to right)

[@p.harika]

@@natasharani20 thank you I was wondering about this.

[@nithya4358]

@@natasharani20 you mean electron affinity?

[@manmohanbisht69]

So can we say at room temperature donor level has no meaning...cuz all the electrons will jump to CB.

[@mahnoormumtaz3658]

Why are the holes not produced when the electron from phoshphorus jump to conduction band??

[@lewtube6436]

It looks to me like the reason the positive phosphorus ions don't behave like holes is because the free electrons don't fall into them. They move into the conduction band and stay there with what little heat it takes to get them there. With intrinsic Si, the current movement occurs by electrons falling into Si holes and being pulled out. (I may be wrong.)

[@fay407]

Any one know what is the application he uses to make this presentation and drawing ?

[@Dolphin_180]

Same question, did you find it out?

[@fay407]

@@Dolphin_180 no 😓

[@rishabhranjan9168]

❤️❤️❤️

[@CGuevara00]

¡Thank you!

[@raskkas6201]

what happened to the holes in phosphorous atom?

[@KhanAcademyIndiaEnglish]

Phosphorous atom doesn't have a hole, mainly because it's octet is satisfied by the 4 covalent bonds

[@MohanKumar-mw1pm]

@@KhanAcademyIndiaEnglish can due to thermal agitation, the phosphorus can give a hole by leaving an extra electron

[@sktfaker489]

after losing 1st electron phosphorus becomes +vely charged. So its effective nuclear charge (Zeff) increases. So it is not easily possible for phosphorus to give 2nd electron. Hope it helps :)

[@girishdeshpande6843]

4:34 What math are we talking about? Can someone pls explain...

[@miscellaneousgaming8533]

That's just the highest energy level of phosphorus compared with silicon

[@delusionalplatonist6077]

schrödinger-born equation to find the probability of finding an electron at a given position. It's a very complicated stuff though

[@phasorsystems6873]

Simulate some circuits! explore androidcircuitsolver on google

[@jeswynnn]

I've phy boards in a week. It's 4am. I've been grinding for hours. Anyone else w me?

[@shubham_bandhavakar8826]

I used to watch this when I was learning I have my physics board today and I love his explanations for revision in 2x

[@ajaythalaiva1631]

YOU TRYING TO IMITATE SAL KHAN........LMAO