102N. Basic Solid-State Physics: Doping, Carrier Density, Distributions

[@versatileguy87]

This is highly informative and a good brush-up of fundamentals of device physics. Thank you for providing such knowledge for free over KZbin. :) I genuinely appreciate your efforts and have even recommended to my friends.

[@luismeza1435]

This is the best explanation I've had about these topics. Very helpful!

[@ericblack1127]

Ali Hajimiri is a national treasure.

[@deepakmecheri4668]

Glad to see that you're uploading again professor

[@yeslinsequeira4612]

Thank you so much for putting these up online

[@MrGyulaBacsi]

According to that figure that was sketched at around 29:28 (where the F-D distribution was sketched together with the energy-band diagram) the following inequality holds: (E_v < E_f < E_c). But let's assume, that for some E_1 and E_2: E_v < E_1 < E_f < E_2 < E_c. In this case the integral of f(E) from E_1 to E_2 would be a larger than 0 number; this would mean that the probability of finding an electron between the energy levels of E_1 and E_2 is not 0 (it is possible). But the whole idea of these bands and the bandgap is that the electrons could only be either in the valence band or in the conductance band, and not in between them (in the bandgap region). Is there a contradiction here somewhere? Or am I missing here something?

[@CrazyMineCuber]

I have the exact same question :(

[@MrGyulaBacsi]

@@CrazyMineCuber it seems I was lazy enough not to read all the comments before posting. One of them - that was there way before I placed the question - is roughly about this same concern. And the professor seemed to answer that.

[@CrazyMineCuber]

@@MrGyulaBacsi Thank you for pointing that out! But embarrassingly enough I to saw just after I wrote the comment. Now I just wish I could find somebody that can explain fermi-statistics and density of states as well as Ali.

[@tkshz6150]

Very good lecture. Just curious what textbook you recommend for this course? Thank you!

[@guertinD61]

I don't understand the concept of n_i. At some points it seems to be the electron density in silicon, but at other points it is the number of electron-hole pairs that may be produced in silicon for example if n_i = n = p. The number of pairs produced would be dependent on the temperature.

[@abcddd580]

21:17 If the Fermi-Dirac distribution gives the probability of finding an electron at an energy E, then is the distribution really an envelope of a discrete distribution? I ask because if it were a continuous distribution, the probability of finding an electron with any given energy should be 0.

[@harshavardhan9399]

it's a continuous distribution and yes probability of finding any electron with certain energy is 0. all you can find is probability of electrons with certain range of energy like from E1 to E2

[@felixchen946]

Hi Prof. Hjimiri - I have a question that hope you could provide a comment on. When you showed the Fermi Dirac probability function at K, it seems to violate bandgap where no electrons should be found? If the probability around Ef jumps from 1 to 0, I couldn't understand where the bandgap is? Thank you so much for your time.

[@AliHajimiriChannel]

That is the distribution if all energies are allowed. The actual density is the product of the distribution and the density of states (which is zero within the bandage).

[@felixchen946]

@@AliHajimiriChannel thank you Prof. I so appreciate!!

[@joorashis6277]

What book 📖 or series of books that can make me understand the fermi Dirac and boltzman distribution basis and derivations cause I don't have this Basics ?

[@majeedanwar9993]

dear sir, would you recommend any book to follow and solve problems

[@seinfan9]

What type of course is this where the lectures span multiple hours? Is this something common for those on the quarter system rather than on a semester system?

[@pras7803]

Sir, What Book do you recommend for reading along with this course (if any)? Love your lectures!

[@AliHajimiriChannel]

We are planning to release the lecture notes and handouts soon.

[@pras7803]

@@AliHajimiriChannel Thank you sir for your reply , That will be really helpful!

[@jakubjirsa317]

​@@AliHajimiriChannel may I know when are you planning to release them? And many thanks for amazing lectures!

[@colinm6672]

Can anyone confirm if these lecture notes where released and on what platform if yes?

[@muhammadishtiaq4331]

Sir does energy of phonon in crystal depends on speed of wave in that crystal?

[@shaizanbhat7826]

In love with Device physics series..... Thank you Sir! .... I just had one doubt regarding the effective DOS and DOS, i'm not able to find a proper meaning and definition of this in any text book. Can you please elaborate it more ?? if it is the states near the conduction band edge but DOS in 3D is proportional to square root of E-Ec, so if E=Ec, DOS=0 ... What basically is Effective DOS then?

[@baharaliali2377]

sir energy state of s sheets we called ?

[@robertwilsoniii2048]

So this is how cpus work, they manage potential energies to maintain steady states or equal generation and decoherence.

[@kchaitanya7267]

sir according to pauli exclusion principle electrons distributed in different energy bands/levels then how come the fermi distribution is continuos(for example hydrogen atom energy levels are 13.6ev,3.4ev,1.5ev and so on.so the fermi distribution should be just pulses around these energy levels)

[@nobodynowhere7163]

the lecture would go a lot faster if he wouldn't pause waiting for the students to answer his questions.