Band Definition and 531 Threads

  1. M

    Step PN Junction - Energy Band Diagram

    A step pn junction diode is made in silicon with the n side having N'D = 2x10^16 cm^-3 and the p side having a net doping of N'A = 5x10^15 cm^-3. 1). Draw to scale the energy band diagram of the junction at equilibrium. 2). Find the built-in voltage, and compare with the value measured off...
  2. Loren Booda

    Electron band structure in a nucleus

    Consider a nucleus with N neutrons and Z protons. Can one justify it alternatively as a nucleus with N + Z protons and N electrons, the latter occupying orbitals either confined to the nucleus or following beta decay according to their electronic potential?
  3. I

    Understanding the band profile diagram in a junction

    I am confused here and hope to get help from you physicians..the assistant in the uni could not help me.. when we have a junction between two materials with different fermi levels, for example a metal and a semiconductor, we say the fermi level of the semiconductor gets shifted till it's equal...
  4. M

    E-K Diagrams, valence band, conduction band

    I'm having difficulty figuring out how to work this problem: Assume a material has a given E-K diagram: E(K)conduction = Ec + E1 * sin^2 (Ka) E(K)valence = Ev - E2 * sin^2 (Ka) a=0.5nm E1 = 5eV E2 = 4eV I have to: * sketch the E-K diagram for the first brillouin zone (-pi/a < k <...
  5. N

    What is the Conduction Band and How Does it Affect Material Properties?

    Anyone please explain to me what is conduction band and what are conduction band electrons? What energy do they have and how do they transfer it?
  6. B

    What causes band gaps in acoustic systems?

    Not sure if this should have gone in help but here goes. I'm doing some background reading into the subject covered by my final year project for my degree. In particular I'm trying to get a grip on the topic of band gaps (acoustic to be exact but I'm looking generally at the moment)...
  7. L

    Q:How to interpret band structure?

    Dear all: I've been tortrued by this problem for a long time, please help me as possible as you can. 1. I want to know, after one get a dispersion picture of E(k), how to judge one of those curves stems from, say, px/py/pz sigma/pi (bond?)? That is to say, how to judge the curve's...
  8. J

    Schottky contacts - band bending

    Hello! I am looking a bit at the Schottky contacts, metal-semiconductor, and I am starting to get a hang of it, but some things are missing. Specifically: Why must the distance from the Fermi Energy to the vacuum level in the metal and the distance from conduction band edge to vacuum...
  9. I

    My band got offered a record deal the other day

    My band got offered a record deal the other day! Hooray! :biggrin: We haven't actually signed anything yet so maybe I'm being premature in posting this but I'm too excited not to. I've been trying really hard not to get excited about it till it's definite but I've just burst! Yay!
  10. S

    Exploring Band Theory & the Role of Even Cell Contributions in Insulators

    I have a question about insulator. The story starts from the fact that, taking a 1-D model, there are N possible values of wave vectors k within the first Brillouin zone [becasue number of possible k's = (2*Pi/a)/(2*Pi/L) = L/a = N where L is the length of the crystal, a is the distance...
  11. H

    The best band you've never heard of

    I humbly submit to you, The Comas. I've been into them for a while, but the other night I attended one of their shows, which pushed everything over the edge into the slavish obsession of repeated looping listenings. The Comas' tendrils are now seeping into every one of my brain's sulci and...
  12. G

    Boost Your Physics Project with Rubber Band Testing Help!

    Hello everyone My phisicsproject for school is to test the strength in every rubber band in a bag with new fresh rubberbands. The problem is i can't really understand how I should do this test, and i hop you guys can help me out. //daniel :confused: <-- me right now :-p
  13. S

    Investigating Proportionality of Elastic Band Range to Pull-Back Length

    im doing a lab tomorrow that i must plan soon. if we fire an elastic band, the length we stretch it will affect the range but how do i support my hypothesis that range is proportional to pull back length? do i use hookes law assuming that pull back length is the same as extention? any tips...
  14. L

    Help: How to interpret energy band?

    As we all known, energy band is very important to everyone who want to go longer in physics, especially in condensed matter physics. However, as a student of physics, I am shamed to say that I cannot interpret the picture of energy bands well, thus would someone be kind to tell me the secret or...
  15. S

    Looking for a good band name having to do with the origin of the universe

    Hello :smile: I'm searching high and low for a new band name, having to do with the origin of the universe... it has to sound cool... I wish the Big Bang theory was called another way...any ideas anyone? thanx :biggrin:
  16. Y

    Need help on rubber band and Hooke's Law

    This has caused me to be very confused because at one time i did an experiment, the rubber band followed Hooke's Law, but at another time, it does not. When I search the internet, some websites state that such experiments are only correctly done when the force is linear with the extension...
  17. D

    Can Compression Turn an Insulator into a Metal?

    Hello, I am in the middle of revising topics for the materials section of myend of year exam. For some reason my department give out past papers but do not give out answers. Any answers to any of the follwing questions would be very helpful. I don't think too much detail is required just a...
  18. D

    Calculation of the band structure of Si

    Please, help me to calculate the band structure of Si using the pseudopotential method. I will appreciate if you send me a simple program of calculation in any programming language very much and will be very grateful for any link or reference. The problem is than I've read the pile of books and...
  19. K

    What is the difference between dual band and tri band cell phones?

    What do they mean w.r.t Cell Phones ?
  20. Ivan Seeking

    What is the cause of the mysterious blue band surrounding Jupiter?

    http://www.abc.net.au/midnorthcoast/stories/s1057580.htm
  21. B

    Black and White Mirror / Narrow Band Mirror

    I am looking for a mirror (11" x 14") that reflects only shades of gray. Ideally the reflection would be like a black and white photo (The subject's reflection would be "black and white"). Is such a mirror available? If not, can one be made? If so, by whom? Thank you for your assistance.
  22. P

    Exploring the Science of Rubber Bands: The Force Behind Elasticity

    OK, maybe this is an odd question, but here goes: When I pull on a rubber band, is the force I "feel" the resistance to co-valent bond separation? Am I actually "feeling" electron forces?
  23. Z

    Rubber Band Powered Mass Transporter

    I need help. I need to design a device to transport a 1kg pass ten meters over a level surface using the energy stored in a #10 rubber band. I decided to use three wheels at the structure, and i created a car with a basswood top and the rubber band is wounded up at the rear axel to get power...
  24. A

    Constructing a Vehicle Powered by a Rubber Band:

    A Rubber Band?? OK...i need your help people... i have to construct a vehical that can transport a 1 Kg weight over 10 meters using any materials i please...here's the catch: Its only source of power can be a size-10 rubber band! It can have no other source of power and it cannot be launched...
  25. A

    Experiments to describe the band structure of bulk (solid) materials?

    Experiments to describe the band structure of bulk (solid) materials? I just want to know the name of some of the most used techniques to describe or obtain information of how the band structure of the material is. Not by theorethical calculations, just experiments. For example, let say I...
  26. B

    What Components Create a 7 kHz Cut-Off Frequency in a Passive Band Pass Filter?

    hi there ive been attemping this question and i cannot find the equation to work it out anywhere ! any help would be great ! for a passive band pass filter from the following list choose the three components which would produce a cut off frequency closest to 7 khz and a band width...
  27. B

    Band Pass Filters: Formula for Calculating

    does anyone know the formula for band pass filters. thanks
  28. J

    How Does Weight Affect the Stretch Length of Rubber Bands?

    rubber BANDS hi guys i was just wondering what the relationship between the weight and stretch length of rubber is. And also why does an 8cm rubber band increase it's stretch length by 5cm at 600gms weight while the trend before and after is every 10gm added to the weight adds 0.2 to to the...
  29. Greg Bernhardt

    What is Joe's faovorite band? And why

    Chad's favourite band is Aerosmith. Dan's favourite band is Spinal Tap. Pheobe's favourite band is the Red Hot Chili Peppers. What is Joe's faovorite band? And why. Choose from: Take That Rolling Stones Blues Brothers Kiss
  30. P

    Can You Identify This 80s Band From Their Lyrics?

    There was a band that I loved back in the early 80s back from my youth so to speak. For the life of me I can't rememeber the name of them. But I know fragments of a song. I don't know if they belong to the same song or not. They are "Ain't them cats the most, just rock'n from coast to coast...
  31. Chi Meson

    Top 10 Physics-Related Names for Bands

    I wanted to get a top ten list of best Physics related names for rock bands, jazz groups, etc. The most obvious one, but still a good one, would be: "Heat Death" (heavy metal, of course). Another one that I think already has been used is : "Schroedinger's Cat" (Progressive...
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