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Drift velocity in a resistor?

  1. Jan 29, 2012 #1

    An Si resistor is at 300Kelvin, and is 100μm long, 1μm thick, 5μm wide. The conductivity is 7.128 Ωcm. The resistance is 28058Ω. A voltage of 5v is applied. What is the drift velocity of the electrons, given that n = 1.01x103?
    Other constants:
    μn = 1350 cm2/Vsec
    μp = 450 cm2/Vsec
    My work:
    So basically,
    I have the formula Jn,drift = qn(μnE).
    The question asks for drift velocity, does that mean I'm trying to find Jn,drift or just the mobility factor μnE? What exactly is Jn,drift? In either scenario, how do I find E field if I'm only given a voltage? It's not like I can integrate b/c Voltage is constant through the resistor.
    I was also considering using I = nqvdA. But I was getting some outrageous velocity with this.
    Thank you.
  2. jcsd
  3. Jan 29, 2012 #2
    Jn,drift is probably the drift current of negative carriers (electrons). In a semiconductor you may have also drift current of holes as well as diffusion currents of both types of carriers.
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