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Semiconductor physics

Bad Chemicals · 2013-01-03 16:58:18

Can anyone explain what the equation np=Nc^2(e^(-Eg/kT)) signifies. I know np = ni^2. Is Nc^2 here ni^2 (i.e. free charge carriers) or is it the overall number of charge carriers? I assumed that Nc^2 was the total number of charge carriers, so that Nc^2(e^(-Eg/kT))=ni^2, but that is not the case. Also can anyone explain,…

03-01-2013 05:58PM

#1

Bad Chemicals

Registered Users, Registered Users 2 Posts: 66 ✭✭

Join Date: March 2009

Posts: 41

Can anyone explain what the equation np=Nc^2(e^(-Eg/kT)) signifies. I know np = ni^2. Is Nc^2 here ni^2 (i.e. free charge carriers) or is it the overall number of charge carriers? I assumed that Nc^2 was the total number of charge carriers, so that Nc^2(e^(-Eg/kT))=ni^2, but that is not the case.

Also can anyone explain, if given ni=1.5x10^16m^-3, and electron and hole mobilities are 0.13m^2V^-1s^-2 and 0.05m^2V^-1s^-1 respectively, how to find the conductivity of the doped silicon at 300K, if there is one donor impurity per 10^8 silicon atoms. I looked up the density and found the carrier concentration that way, but there must be some way to do it given the info above!
Thanks anyone who can help.

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