Oxford Solid State Physics 2015
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Chemical Potential and Temperature Limits in Doped Semiconductors

Posted by Saad on April 19, 2015, 6:12 pm

 How do we deduce the temperature dependence of the chemical potential for a doped semiconductor (question 4.6(c)(i) and (ii))? Considering the complication and vagueness of the temperature ranges below, I'm unsure... For the law of mass action to be valid, we require: (E_c - mu) >> k_B*T (mu - E_v) >> k_B*T For a n-doped semiconductor to show intrinsic behaviour, we require that I>>D, where I=(np)^1/2 and D=n-p. This puts a lower bound on temperature. How do we know that such a temperature (and mu(T)) satisfy the two conditions above? ONLY then can we use the law of mass action to obtain I... Also, what is the temperature for no freeze-out? It would seem to me for no freeze-out in an n-doped semiconductor: k_B*T ~ (E_c - E_donor band) We know that chemical potential at T=0 is midway between E_c and E_donor band, so it better be much below E_donor band at temperatures (including the above) where the donors are ionised (ie. no freeze-out). Otherwise, the law of mass action won't be valid!
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 Message Thread Chemical Potential and Temperature Limits in Doped Semiconductors - Saad April 19, 2015, 6:12 pm Re: Chemical Potential and Temperature Limits in Doped Semiconductors - Steve Simon April 21, 2015, 8:09 pm Re: Chemical Potential and Temperature Limits in Doped Semiconductors - Saad April 21, 2015, 8:37 pm Re: Chemical Potential and Temperature Limits in Doped Semiconductors - Steve Simon April 21, 2015, 8:45 pm Re: Chemical Potential and Temperature Limits in Doped Semiconductors - Saad April 21, 2015, 9:35 pm Re: Chemical Potential and Temperature Limits in Doped Semiconductors - Steve Simon April 23, 2015, 2:39 pm « Back to index

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