Semiconductor Doping

[@jw3983]

thanks for this video too! Even if this does not really matter for the discussion about semiconductors, but from a chemists point of view you should be careful with drawing double bonds within a Si-Crystal. One line in these lewis drawings is in general meant to consist of 2electrons overall (one electron from each atom). Assigning eight bonds to each Si atom would therefore mean each Si-atom contains eight electrons in its valence shell, involving its d-orbitals in bondings. Besides of that your physical discussion about this topic is absolutely outstanding!

[@poulamibag2660]

The videos are soooo easy n fun to understand........electronics n especially semiconductors was never this interesting to learn....THANK YOU :)

[@JordanEdmundsEECS]

Thanks :) Very glad you enjoy them, semiconductors are pretty awesome :D

[@jw3983]

thanks for this creat series of educational videos!

[@UsmanKhan-qp1vp]

You need to do a class in Chemistry.... impossible for Si to have 8 bonds, only 4 possible and P can only have 5 bonds max. and when P fills its valence band it will fill one electron in 3 orbitals and 2 electrons in one as that is the most favorable position..... the same way I as a Chemist need to learn basic Physics. Thank you for content

[@JordanEdmundsEECS]

Yup this was my mistake, there are other comments to this effect xD

[@user-ge8hj9br6w]

4:44, that postive charge is not a hole because, that + has to do with the nucleus, its like nucleus was added with one extra proton.

[@JordanEdmundsEECS]

Yup, that’s exactly what a “hole” means! That’s Why it’s called a “hole” and not a “positive electron”

[@ruicao7054]

The product of the total concentration of electrons and holes in a doped semiconductor, at equilibrium, is a constant (np=ni²), so in a n-type semiconductor the hole concentration actually decreases comparing with intrinsic semiconductor...

[@vismutti1656]

Sir, could you explain why phosphorus becomes positive after losing one electron while other silicon atoms give it four electrons and it's more electronegative so it hugs those electrons tighter?

[@619pettu]

Phosphorous has atomic number 15, So orbitalwise 5 electron on its valence shell. only 4 electrons take part in bonding to the adjacent silicon atoms, so from the ‘silicon crystal’ point of view! the lattice has got an extra “free electron” for conuction. So once that “free electron” goes for conduction, Phosphorus atoms gets one +q charge and becomes positive ion

[@user-ge8hj9br6w]

will the absolute value of Ec changes after doping?

[@JordanEdmundsEECS]

Nope

[@khalnayak5684]

But when Boron bonds with 4 Silicon atoms , it makes double bonds with each atom, so for making a total of 8 bonds , it should have 8 electrons, but it has 3 ... So shouldn't total charge be +5 ?

[@khalnayak5684]

I'm confused now, it makes a single or double bond ?

[@JordanEdmundsEECS]

It makes single bonds which requires 8 electrons. 4 of those come from the neighboring SI atoms, and the other 3 from the boron, leaving it with a -1 charge (if it only had 7 electrons total it would be neutral).

[@khalnayak5684]

@@JordanEdmundsEECS Thanks dude 😁

[@UsmanKhan-qp1vp]

B can only form 3 covalent bonds with Si since it only has 3 electrons. the remaining orbital is electron free, hence it behaves like a hole.

[@williamcribbs1165]

Should n-type and p-type be flipped?

[@williamcribbs1165]

Oh I am sorry I just rewatched the clip I am good now!