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.
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.
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.??
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).
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?
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.
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🤩
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
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
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 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.
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.
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
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.
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.
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 :)
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
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.)
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 :)
Why is this only on Khan Academy India? Should be on the normal Khan Academy for more people to see! Excellent content
well maybe because in most first world countries this is taught in colleges while in India we learn this in school
@@amalsrivastava6853 that's true... I'm in class 12th so kinda can figure out 😅
@@amalsrivastava6853 that's your misconception
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.
@@hibudy I agree that ...
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.
I get goosebumps listening to these amazing explanations!!! Love it!!!
I AM SO THANKFUL TO THIS MAN 🙏
He explains wonders 💯
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.??
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).
@@KhanAcademyIndiaEnglish Thank you so much sir
Your explanation , voice and colourful graphical representation is very nice..
I luv your teaching and you clear all my concept
These videos are brilliant. I work for intel in components research. Enjoying your content !. Thank you Mahesh Shenoy
extremely useful
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?
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.
@@KhanAcademyIndiaEnglish thanks 🙏
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🤩
I do agree as none made clear this concept!
thank you very much.. this is great
Excellent!
Its really helpful 😊. Thanks for clearing all the doubts
The name extrinsic means that something external was added, i.e., the material was doped.
Thank you so much. I helped me alot
Excellent explanation
The explanation is very good🙂☺☺
you are genius!
Excellent 🤗
this is called ''the best''
Yes bro
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
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
Hello Sir why phosphorus having energy level nearer to the conduction band???
Why donor level decreases for group 16 and 17 elements???
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
Even I have same question but no one there to clear.
@@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.
@@gurwinderkaur7104 thanks a ton for your explanation I was wondering it from long time
@@p.harika your welcome:-)
It's an awsm explanation
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
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.
Could you please explain why donor level of sulphur is close to the valance band?
11:01 What math are we talking about? Can someone pls explain...
When the phosphorous becomes positive, and the electrons move to the conduction band, do the holes left move to the valence band or no?
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
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.
Excellent 👌👌👌👌
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.
Good question, this is explained in detail in another video named "majority & minority carriers"
Dude phosphorus usually after donating e- becomes +vely charged. it does not create holes usually. :)
why not use group 16 elements or group 12 elements
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 :)
Sir ,Can we use carbon atoms as a semi conductor?
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
@@arshad4695 That is an exception due to its layered structure, there is one loosely bound electron that gives conductivity
Shockingly good explanation sir. I would like to subscribe to your magazine.
Could you please explain why donor level of sulphur is close to the valance band as he described in the video?
Much Respect 💛
Thanks 🤩
So can we say at room temperature donor level has no meaning...cuz all the electrons will jump to CB.
good explanation sir
thank you
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
❤️❤️❤️
Which software is he using
exactly? did you find out?
It looks like some sort of Autodesk software (maybe Sketchbook?)
Paint 3D on windows 10
¡Thank you!
Why are the holes not produced when the electron from phoshphorus jump to conduction band??
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.)
Why the donor level is shifting downwards while using S and Cl respectively
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)
@@natasharani20 thank you I was wondering about this.
@@natasharani20 you mean electron affinity?
Any one know what is the application he uses to make this presentation and drawing ?
Same question, did you find it out?
@@Dolphin_180 no 😓
Simulate some circuits! explore androidcircuitsolver on google
what happened to the holes in phosphorous atom?
Phosphorous atom doesn't have a hole, mainly because it's octet is satisfied by the 4 covalent bonds
@@KhanAcademyIndiaEnglish can due to thermal agitation, the phosphorus can give a hole by leaving an extra electron
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 :)
4:34 What math are we talking about? Can someone pls explain...
That's just the highest energy level of phosphorus compared with silicon
schrödinger-born equation to find the probability of finding an electron at a given position. It's a very complicated stuff though
Instead of doing this why can't we just use a conductor
I've phy boards in a week. It's 4am. I've been grinding for hours. Anyone else w me?
I used to watch this when I was learning
I have my physics board today and I love his explanations for revision in 2x
YOU TRYING TO IMITATE SAL KHAN........LMAO