Recent content by metroplex

  1. M

    Step PN Junction - Energy Band Diagram

    back to the top for the evening crew.
  2. 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...
  3. M

    Question: Where Can I Find Affordable Rechargeable Batteries Online?

    www.craytonelectronics.com AAA NiMH for $0.69/ea AA NiMH (2.3 AH) for about $1.50/ea or less in bulk. Use the coupon code "MUNI" for free shipping. The site looks poorly made but I've ordered from them before and a lot of people at work have ordered from them as well (without any problems).
  4. M

    E-K Diagrams, valence band, conduction band

    I decided to pick K=0 for the minima of the conduction band and the maxima of the valence band (does this sound right?) solving for the 2nd derivative: E(K)c = Ec + 5ev * sin (K*a)^2 E(K)c" = -10*sin(Ka)^2 + 10*cos(Ka)^2 Evaluate m* = hbar^2 / E(K)c" = 1.11x10^-69 (units?) E(K)v = Ev...
  5. M

    E-K Diagrams, valence band, conduction band

    a = 0.5 nm I must have drawn the E-K diagrams wrong because the maxima/minima occur at K= -pi/a, 0, and pi/a
  6. M

    E-K Diagrams, valence band, conduction band

    Solving for the 2nd derivative at the maxima/minima, I get 0. :confused: if you plot out the graphs, the maxima/minima are at the same K values for both curves?
  7. M

    E-K Diagrams, valence band, conduction band

    I graphed them on the calculator and using Ec and Ev as variables (but assume they are zero with the calculator), the graphs are symmetrical about the x-axis (y=0). Does that make any sense? For the effective mass, how do you use the 2nd derivative? Isn't it just the slope? if so, how does...
  8. M

    E-K Diagrams, valence band, conduction band

    So I just treat Ec and Ev as variables and mark them arbitrarily on the y-axis for each of the curves? I graphed them on my calc and they appear to be just almost symmetrical of one another. So do I have to solve for a numerical value of the effective mass? Is there a difference between...
  9. 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 <...
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