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to find mobility

Can any one tell me how to find mobility if only hole or electron concentrations are known??

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    Michael Laube

    Hello rajeev,

    i hope i can help you. I assume that you are speaking about typical semiconductor like SiC, which is either n-type or p-type. I further assume that you are interested in experimental determination.

    From experiment it fairly straight forward to obtain mobility at low fields. First you measure the resistivity rho, then you measure the low field Hall constant Rh, and you get the so called “hall mobility” µH=Rh/rho

    Now the Rh is related to the majortiy carrier concentration n by Rh=rh/n (for n-type).

    You can mix the formulas to calculate the mobility if you know both carrier concentration and resistivity.

    However, you should be aware that the mobility which you get from hall effect, differs from the drift mobility by the so called “hall scattering factor” rh. There exist some theoretical estimates for rh-value (depending on the type of scattering), and there is also experimental data published on rh (at least for Si and SiC, as far as i know), but usually people set rh=1 to make the life easier ;-)

    i hope this answer is helpful. If not, could you please be a little bit more specific.

    have a nice day

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