PN Junction Introduction

[@benwhitney4549]

I'm sorry for such a repetitive comment, but I need to say: thank you for your videos. They are fantastic and explained so well. I'm using them to help me in my college class. My professor is amazing but getting two different, well stated explanations is vital for my learning process.

[@sujoypaul1874]

I am whole heartedly thankful to you for these simple videos,so ordinary students can understand complex topics

[@zworm99]

I just have to say this whole semiconductor physics series is fantastic! I´m a physics engineer student from Sweden currently taking a course in solar cells and unfortunately our textbook is lackluster to say the least and our teacher not too pedagogical (not to mention hard to reach due to the current pandemic). Your videos really helps with the intuitive understanding of the subject and they make me even more excited to become a great physicist! Thank you!

[@barneycasting8331]

I was in an interview panel where we interviewed Jordan Edmunds for a position, now I am watching his videos to teach my students! 😂😂😂

[@katieruland6851]

EE masters student and have taken probs 8 classes between now and undergrad where the depletion region of pn junctions/devices is discussed and I've never seen a good explanation and this is great.

[@djoumana549]

I study this on my 2nd year of university in algeria and in english .. I didn't have any better videos than yours Thank u for ur videos ❤️

[@crazy1azy]

بالتوفيق same here 🙏

[@stef-e6y]

I have my renewable energy exam soon, this really helped me out with PV systems!!! Thank you

[@lichifang632]

I was completely confused by my lecturer until I watched your video. Thank you so much!!!

[@kavidiss7959]

Honestly the best explanation. I was dying to find one😭 thank u soooo much.

[@shuvamoy_uchiha_itachi]

After 7 years understanding it in a wholesome manner. Thanks for the beautiful explanation ❤️

[@robertcanberkozturk7725]

im ded

[@HygienicFoodswithHumaira]

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[@somawesome]

I wish I found these videos earlier.

[@rockspoon6528]

I wish I'd LOOKED for these videos earlier.

[@robertcanberkozturk7725]

nope

[@SnoopGotTheScoop]

@@rockspoon6528 BRUH SAME

[@SnoopGotTheScoop]

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[@lwazidick4018]

I'm writing semester in an hour.

[@Tritonmac251]

Thanks for the great and really helpful explanation!

[@JordanEdmundsEECS]

Thanks :D

[@MinuteMayne]

I think it's essential to explain why the holes and electrons move in the first place: diffusion by chemical potential gradients.

[@kiro9291]

my god you made pn junctions a cake walk! thank you

[@suleyman_ct]

Proper accent deserve a hug.

[@tomfa6507]

I wish my professors from the past could explain things like you do, you should become a college professor if you aren't already!!

[@Mido-gi1gw]

So in Summary, In a pn junction, there are four types of charges, movable and unmovable postive and negative charges. The movable postive charges are located in the p-type and the movable negative charges are located in the n-type. Both types are neutral though due to the existence of the opposing unmovable charges. When the p-type and n-type come in contact with each other, some of the movable opposite charges migrates to the opposite type. As they are traveling, they are repelled by the other migrating movable opposite charges, such that the opposite movable charges migrates at the extreme side of each type. The repulsive field created by the moveable charges contains only the unmovable opposite charges, which are constructs the depletion region. In conclusion, the pn-junction consists of 3 regions, the postive region, the depletion region and the negative region.

[@JordanEdmundsEECS]

Almost. Precisely how I think of it up until the “as they are traveling” part. They aren’t repelled by the other mobile charges (because there’s lots of ions there too balancing them out, so no electric field). They instead diffuse into the opposite region and *recombine*, which is how the ions in the depletion region get “revealed” for lack of a better world. It is these ions that are responsible for the electric field and prevent further diffusion. Far away from the depletion region, the semiconductor is still neutral (it has both its electrons and positive ions, or holes and negative ions). The mobile charges don’t make it very far before they recombine.

[@sharvani6133]

The explanation is so clear. Thanks!

[@jiayiliu9128]

These thoroughly explained videos helped me a lot! Thanks

[@emanueltraiger6092]

Some Feynmanish quality of explanation right here

[@JordanEdmundsEECS]

This made me smile

[@Upgradezz]

Huge honor that.

[@robertcanberkozturk7725]

this comment right here officer

[@blakepeters2249]

Thank you so much for this well explained summary

[@loscienzo]

Very helpful 🥦 Thanks a lot! The black background is also appreciated

[@JordanEdmundsEECS]

Thanks! You get an award for first comment with a broccoli 🥦 emoji.

[@ashrafhussein3028]

thanks for this help. am now free from loss of marks. thanks much. I appreciate

[@JordanEdmundsEECS]

Hahaha glad to hear!

[@gekinmepan]

Can someone explain why, at 6:06, the electrons on the P-side arent being pushed back into the N side by the electric field. It seems like electrons are only reactive to an electric field on the N-side. Not on the P-side. This doesn't make sense to me.

[@gekinmepan]

Electrons moving towards the junction in the P-type region leave behind holes which counteract their negative charge. Similarly, holes moving towards the junction in the N-type region leave behind electrons.

[@zaeemAtif]

LOVE, LOVE and LOVE....!!!

[@rosskappa5410]

So can we say that depletion region is only formed by the immobile acceptors and donors which I think you call them ions, which are the ion form of the impurity atoms such as B^-1 for Boron and F^+1 for Phosphorus? and... silicon or any impurity so to say ANY ATOM can not actually move or physically diffuse through the silicon, they are stable where they are, only thing moving is holes and electrons created by them? Isn't hole movement is directly caused by electron movement? When we are talking about hole and electron diffusion, actually there are not 2 particles moving to diffuse to each other. There is only one particle which is electron that tries to diffuse to holes, and the thing we called "hole diffusion" occurs by itself, directly related to electrons when they diffuse since electron is going to leave behind a hole. If you could please answer these... you'd make me and my friends very happy and I promise I will click 40 ads or any number you give +40 that is feasible :D I will do it. Thank you so much for the videos, deeply trying to understanding something is so satifying.

[@JordanEdmundsEECS]

Eeeeeexactly. You are correct on all points. You can think of holes as a "mathematical trick" that make our physics a lot easier to work with. Best of luck in your quest to understand this very rich subject :) If you want to go deeper I'd recommend taking a class on thermal physics and/or quantum mechanics.

[@rosskappa5410]

Wow thank you so much for the answer. The weird thing is I didn't come across with this explanation of holes. Can't say I've studied the books deeply but i'm dissappointed that it wasn't even mentioned in my class. And for the promise I've made, i did it. Thank you for the videos.

[@Odiskis1]

So the diffusion current creates a net charge that again creates an electric field that stops further diffusion? But wouldn't that make the electric field disappear since all diffused charge carriers will recombine and the charge difference would disappear? Is this something that always goes on, but we model it as a stable situation where all free charges are pushed back? I feel like I am missing something or that I've been overthinking this

[@JordanEdmundsEECS]

Yup, you’re precisely correct, except for one subtle point - recombination does not change the net charge in a particular region, as it removes both a positive and a negative charge with no charge - so the E-field will remain after recombination. Other than that you’re exactly correct.

[@Odiskis1]

@@JordanEdmundsEECS Thanks for a fast reply! You "destroy" both hole and electron at the same so the net charge stays the same. That makes sense! Thanks again

[@AnsImran]

Which sources did you use?

[@zharaalipanahi8084]

I understood diodes very well , thanks 🙏🙏🙏🙏🙏🙏🙏🙏🙏❤️

[@mattcorrigan6639]

Why do you say that there are negatively charged bound ions in the p region, and positively charged bound ions in the n region? My intuition tells me the p region has an excess of holes due to positively charged ions

[@lenafd]

because electrons immigrate to the p region to fill in the holes

[@mp3lwgm]

Very “physical” and valuable.

[@assmazurba9810]

thank you so much!!

[@nnamdiene2400]

Great video!

[@joshuafernandes3624]

youre the man

[@AnshulSharma1997]

in the depletion region does the immobile ion causes an electric field or there are electrons and holes which diffused causing an electric field to exist. Moreover its is safer to say as due to no net movement there are no further diffusion but still is we see by diagram, what causes the electron and holes further movement. Is it the immobile ions or what that repel them? And this electric field is created in the space charge region of immobile carrier?

[@lies4212]

why P-type or N-type is neutral although there are minorities in the two sides?

[@oraange]

How do you define a "electron hole " ?

[@JordanEdmundsEECS]

Imagine a bunch of people sitting in chairs, and at first every chair is filled (or every electron occupies a state in the valence band). Then, one person gets up and leaves (an electron goes to the conduction band). There's now an empty chair (an empty state in the valence band), and the people next to that empty chair are free to move in it, or if you think about it backwards, the empty chair (the hole) is free to move.

[@kimtaehyung4353]

My study ASMR 😂

[@xAmiSarahx]

I like it....

[@distrologic2925]

I have always been confused by how the electrons and holes start being repelled by the junction at some point. But now it makes sense. Once equilibrium is reached, the outside parts are charged and attract their respective particles, while the junction is neutral and does not.

[@mikeearls126]

This shit is really cool - who knew? I mean I'm a 52 year old inquisitive person so probably many people knew but I don't think any in my orbit....uh...hahahaha....ugh....

[@amarfakhredine591]

Omg thanks a lottttttt

[@GradientSoln-En]

It was this simple????

[@MichaelTeniente]

DR. KURT LEHOVEC

[@ياعلي-ظ6ج8ن]

طلاب السادس البه ربكم 😂😂

[@prensandre]

EEciler ses verin.