1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Charge density, carrier concentration, or Hall coefficient for Indium Arsenide?

  1. Yes.

    2 vote(s)
  2. No.

    1 vote(s)
  1. Mar 29, 2008 #1
    I've been searching for an acceptable value for the charge density of indium arsenide; that is, the amount of charge per cubic meter. I have been unable to find anything.

    I'm working on a replication of the Hall Effect, and I need an accepted value for comparing my own results. I've searched Google multiple times, and have searched article databases from http://library.mtsu.edu/ ... It seems no one is very interested in something this mundane; it's all semiconductors and "quantum dots" and other complex esoteric material...

    Where else and for what else can one search? ... I've also not been very successful in ascertaining a clear definition of the Hall coefficient; it appears to vary, depending on the type of semiconductor, and whether one is addressing quantum or classical effects ... but one definition I have that I think is valid is simply the reciprocal of the charge density, that is, R = 1/(ne), where n = # of charge carriers / cubic meter (I think some call this the carrier concentration or carrier density; is that correct?)

    Any help or feedback is greatly appreciated.

    Sorry; the poll was meant to ask about the Hall effect... can't find where to edit (or recreate) the poll.
    Last edited: Mar 29, 2008
  2. jcsd
  3. Mar 29, 2008 #2
    This may be stupid, but unless this material is very exotic I would guess it is electrically neutral, in which case it has no net charge density? If so, then I guess what you really want is the mass density, because if you knew that and its crystalline structure then you could make a decent guess as to how many electrons or protons would reside within a given volume, right? With the doping data I guess you could figure out the mobile charge density also?
  4. Mar 30, 2008 #3
    Yes, I have thought about estimating from its molecular density, and this is what I will do if I cannot find an accepted value... and yes, it is of course electrically neutral, but that doesn't solve my problem. By charge density, or carrier concentration, I mean specifically

    r (Greek 'rho') = ne = (# of carriers of charge / unit volume) * (charge of each carrier) = net amount of negative charge / unit volume.

    Is that clear? Sorry if there was any ambiguity. One definition I've seen for the Hall coefficient is then

    R = 1/(ne),

    sometimes with a minus sign, so that R > 0.
    Last edited: Mar 30, 2008
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook