I have a tough question. If a battery is applied, wouldn't the valence electrons (at the very end of the semiconductive material) find easy to get into the conduction band of the metal wires and finally nearby electrons would jump into those left behind holes, creating like an avalanche? That is, the valence shells of the very end of the semiconductive material would be actually "glued" to the positive metal wire(and to their valence shells). Metal wires have their conduction and valence band overlapped. So electrons would say: "Ooh, look, we don't need a hole to fill in, we can directly jump into the metal wire." The electrons from nearby atoms would say: "Hey! Holes got created! Let's jump in!", and so on. This would create an avalanche, right? I think that more easy to say is this: how is it possible that valence electrons, when a voltage is applied, they jump from hole to hole towards the positive terminal of the battery, so that they finally jump into the metal wire? When they reach the final atom of the semiconductor, they just jump into that metal wire? If this is what happens, then why the avalanche (which I tried :)) to explain above) does not happen? Thank you!
Really not an expert here but I think you're thinking of holes as a missing space in a sea and so if there are enough holes that this "sea" must cave in thus creating an avalanche. It's not like that though when you think about it as simply a band which is occupied by electrons. 2 per energy level but it doesn't mean to say it can't have one or no electrons on one energy level. And so nothing will "cave in" no matter how there holes or electrons move or how many vacancies there are. I think that more holes or electrons just mean more conduction. (Ps. I can't really determine what ur question is but this is the answer for my interpretation of what you are asking).
Avalanche does happens in such cases but..here is the thing it happens in a lightly doped junction…which I think u should watch diode 😅…then the ans to your question will be solved🧞♀️
Please clear my doubt. One cannot say the current is due to BOTH electrons and holes. As a convention we can consider only holes instead of electrons. But if done so we can consider only the movement of holes accounting for current. That is we can say the current is completely and only due to electrons or we can say the current is completely and only due to holes. But we cannot say the current is due to both holes and electrons.
I had a similar confusion. So let me clarify. When we say hole current, it's literally the electrons in the valence band (the ones that are participating in covalent bonds and are not 'free'), jumping from one hole to another, in the opposite direction of electric field. However, there are free electrons in conduction band as well. These electrons also move in the opposite direction of the field. This is what we call 'electron current'. So you see, there is indeed two set of electrons constituting the total current. It's just that, for the electrons jumping from one hole to another, it's easier to keep track of holes. So we assume the holes to be moving. So there you have it, you indeed get two sets of current and total current would be the sum of them. Feel free to ask more questions
@@KhanAcademyIndiaEnglish Now I understand. The current in valence band is called hole current in which it is easier to keep track of holes rather than electrons. Thank you for clearing my doubt sir.
@@geojose5045don't know if you'll see this but lemme answer so I can also understand better..when electrons jump to the conduction band ..they leave the space where they used to stay while in covalent bond with neighbouring atom..and that vacant space is called hole..we know that hole is not a particle ..as electrons keep jumping to the conduction band one after another .. holes are also created correspondingly..as more and more electrona fill up these holes... an electric current is created coz of movement of electrons but these electrons are all inside the valence band and we call these current as hole current because it seems as if the holes were moving
Why is it that semiconductors do this? The thing that some of the electrons will break out and create holes. Why cant conductors or insulators do this? Follow up: Why is it that when Silicon is at 300 K , only some of the electrons manage to jump to the higher energy state? Can't all of them do that since they are all receiving the energy? (commented on the khan academy video as well ,not sure if replying) Thanks
Well this is my answer 😊 Conductors have extra electrons…aka free electrons so no holes if electrons move around While insulators mostly don’t have any free electrons ..I.e they attain octet(mostly through covalent 😅 ig) so no electrons to move around On the other hand semiconductors which fall under the 2 have no sufficient electrons and when under external electric field these electrons start to move around ( which is true for any material)so as they move they leave vacant spaces …which is called holes… Now the 2nd question …for semiconductors as temperature increases conductivity increases…so at 300k which is room temperature electrons in Si and any semiconductors experience jump to higher energy state…as for why few…think this way…when energy is provided only a the lucky ones gets enough energy to excite 😅…therefore only a few mange to excite…in case of conductors their valence bands overlaps conductance band therefore all electrons are lucky🙃 however for semiconductors and insulators electrons have to put in an extra effort to move to higher state which only the lucky ones who get sufficient energy does so…so not all electrons are lucky Hope I answered your question though 3 years later😂😅
sir pls clear my doubt I can't understand why you are saying that the valence band is 'completely filled' in semiconductors whereas it's not so in conductor (with reference to your last video), because we know that Si has only 4 electrons in valence shell instead of 8, so even if they form a band, each atom will still be short of 4 electrons, then in what sense do you mean 'completely filled'?
2:50 You talked about the electron in the edge is not shown. But as a bulk material, it definitely has the edge, what is the actual electron configuration in the edge, leaving a vacancy over there?
I agree your point, however, is it possible to create a environment that keep a perfect silicon that without any impurity. In this situation, what does the edge looks like?
Thank you for the great explanations and clear visuals. I love the representation of holes as an air bubble in a water bottle :)
that water bottle and air bubble anology was the best part of the video,
you cracked down such a complex thing with that simple ilustration
I've scored full mark in semiconductors test. Thanks to you for making this chap clear.
You are the best teacher. Great job🔥😃☺️
😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊
i wish this type of explanation would been at my college.college teachers should really learn from this guy
yes dude
Sir your core concept teaching always blows my mind thank you, for such amazing science
Explaination is too good
..
......
Even best😊😊
Thanks for the quality content and the meaningful explanations.
Excellent series; thank you for making these free and public!
As an aside, your handwriting during the intro looks like a Disney font.
Couldn't be explained better. Thanks a lot. 🙂
When you put the knowledge of semiconductors/transistors all together, it is quite beautiful.
"The whole idea behind this hole" that was very nice ;)
11.12 best analogy.Awesome!!!!!👍👍👍👍.Thank you so much sir.
Water bottle explaination is a great idea........
Clear cut concepts in common language & absolutely for free....
Help alot for students, thank u so much ...khan academy hat's off to u👏👏👏
most of the youtubers tends to focus on quantity but loved the way how you focus on quality education. Thank u 🖤
These 11 minutes literally flew by!
Thank you so much, Sir. The air bubble analogy cleared things up well.
Great explanation and effort. May god bless you man.
thanks for the water bottle analogy man loved it!!!!!!
Love your teaching 😊
I have a tough question. If a battery is applied, wouldn't the valence electrons (at the very end of the semiconductive material) find easy to get into the conduction band of the metal wires and finally nearby electrons would jump into those left behind holes, creating like an avalanche?
That is, the valence shells of the very end of the semiconductive material would be actually "glued" to the positive metal wire(and to their valence shells). Metal wires have their conduction and valence band overlapped. So electrons would say: "Ooh, look, we don't need a hole to fill in, we can directly jump into the metal wire." The electrons from nearby atoms would say: "Hey! Holes got created! Let's jump in!", and so on. This would create an avalanche, right?
I think that more easy to say is this: how is it possible that valence electrons, when a voltage is applied, they jump from hole to hole towards the positive terminal of the battery, so that they finally jump into the metal wire? When they reach the final atom of the semiconductor, they just jump into that metal wire? If this is what happens, then why the avalanche (which I tried :)) to explain above) does not happen?
Thank you!
Really not an expert here but I think you're thinking of holes as a missing space in a sea and so if there are enough holes that this "sea" must cave in thus creating an avalanche. It's not like that though when you think about it as simply a band which is occupied by electrons. 2 per energy level but it doesn't mean to say it can't have one or no electrons on one energy level. And so nothing will "cave in" no matter how there holes or electrons move or how many vacancies there are. I think that more holes or electrons just mean more conduction. (Ps. I can't really determine what ur question is but this is the answer for my interpretation of what you are asking).
Avalanche does happens in such cases but..here is the thing it happens in a lightly doped junction…which I think u should watch diode 😅…then the ans to your question will be solved🧞♀️
Please clear my doubt. One cannot say the current is due to BOTH electrons and holes. As a convention we can consider only holes instead of electrons. But if done so we can consider only the movement of holes accounting for current.
That is we can say the current is completely and only due to electrons or we can say the current is completely and only due to holes. But we cannot say the current is due to both holes and electrons.
I had a similar confusion. So let me clarify.
When we say hole current, it's literally the electrons in the valence band (the ones that are participating in covalent bonds and are not 'free'), jumping from one hole to another, in the opposite direction of electric field.
However, there are free electrons in conduction band as well. These electrons also move in the opposite direction of the field. This is what we call 'electron current'.
So you see, there is indeed two set of electrons constituting the total current. It's just that, for the electrons jumping from one hole to another, it's easier to keep track of holes. So we assume the holes to be moving.
So there you have it, you indeed get two sets of current and total current would be the sum of them.
Feel free to ask more questions
@@KhanAcademyIndiaEnglish Now I understand. The current in valence band is called hole current in which it is easier to keep track of holes rather than electrons. Thank you for clearing my doubt sir.
@@veluv9879 but how can there be current in the valence band. Current can only be generated in the conduct band right?
@@geojose5045 No . The current flows through both valence and conduction band.
@@geojose5045don't know if you'll see this but lemme answer so I can also understand better..when electrons jump to the conduction band ..they leave the space where they used to stay while in covalent bond with neighbouring atom..and that vacant space is called hole..we know that hole is not a particle ..as electrons keep jumping to the conduction band one after another .. holes are also created correspondingly..as more and more electrona fill up these holes... an electric current is created coz of movement of electrons but these electrons are all inside the valence band and we call these current as hole current because it seems as if the holes were moving
Such a wonderful explanation😊😊 the concepts are crystal clear. Amazing video sir👏👏👏
Legendary teaching skill! Thanks a lot sir. ❤️❤️
Next level teaching soo far 😘😘😘😘
this video ended with a the analogy of the decade
this is such a good explanation wth my mind is blown
Your videos are amazing and easy to understand.
Wow it's a beautiful explanation
Wow Art of physics!!!!😘😘😘
God of teaching
hats off to you sir!!
Thanks a lot.
Wow this is such a great explanation!!! thank you!!!
This was so helpful thank you!!
Loved the analogy 🤌🤌
tnx sir ,i have big respect for u . but i have 1 question over here how can holes can move
You write in Disney font
Fr fr
Fr fr fr fr
Fr fr fr fr fr fr
Last example was awesome... but why i came to utube bs ur app was nt working😯😯
Why is it that semiconductors do this? The thing that some of the electrons will break out and create holes. Why cant conductors or insulators do this?
Follow up: Why is it that when Silicon is at 300 K , only some of the electrons manage to jump to the higher energy state? Can't all of them do that since they are all receiving the energy?
(commented on the khan academy video as well ,not sure if replying)
Thanks
Well this is my answer 😊
Conductors have extra electrons…aka free electrons so no holes if electrons move around
While insulators mostly don’t have any free electrons ..I.e they attain octet(mostly through covalent 😅 ig) so no electrons to move around
On the other hand semiconductors which fall under the 2 have no sufficient electrons and when under external electric field these electrons start to move around ( which is true for any material)so as they move they leave vacant spaces …which is called holes…
Now the 2nd question …for semiconductors as temperature increases conductivity increases…so at 300k which is room temperature electrons in Si and any semiconductors experience jump to higher energy state…as for why few…think this way…when energy is provided only a the lucky ones gets enough energy to excite 😅…therefore only a few mange to excite…in case of conductors their valence bands overlaps conductance band therefore all electrons are lucky🙃 however for semiconductors and insulators electrons have to put in an extra effort to move to higher state which only the lucky ones who get sufficient energy does so…so not all electrons are lucky
Hope I answered your question though 3 years later😂😅
sir pls clear my doubt
I can't understand why you are saying that the valence band is 'completely filled' in semiconductors whereas it's not so in conductor (with reference to your last video), because we know that Si has only 4 electrons in valence shell instead of 8, so even if they form a band, each atom will still be short of 4 electrons, then in what sense do you mean 'completely filled'?
Si is 4 electrons bonds with another si 4 electrons around it.. like a mutual understanding..
can we contribute to the translation of the subtitles in other languages?
2:50 You talked about the electron in the edge is not shown. But as a bulk material, it definitely has the edge, what is the actual electron configuration in the edge, leaving a vacancy over there?
I agree your point, however, is it possible to create a environment that keep a perfect silicon that without any impurity. In this situation, what does the edge looks like?
Thanks jeez! Too good!!
thank you!!
Thank you very much for all your videos
Perfect 👍😊
in this the valence band electrons are of 3s or 3p, there is some vacancy in case of 3p
Is there any change in holes number in valency band if we add phosporous atom
On a Mission to make kotaphysics free and easy to all #neet #jee
08:34 "the whole idea behind the hole..."
¡Thank you!
I’m Finna score full marks in the jee
the hole idea about the hole..
hehehe
Nothing
Compared to organic chemistry