Lecture6(3)

Intrinsic concentration ncentration vs intrinsic

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Unformatted text preview: entration change of 5 orders of magnitude. EE 332 Spring 2013 aCarrier Concentration vs. Intrinsic Concentration rrier Concentration vs. Intrinsic Concentration ncentration vs. Intrinsic Concentration Carrier Density p-type n-type p0 n0 ni -0.05 0.00 0.05 EF-EFi (eV) EE 332 Spring 2013 Carrier Concentration in Semiconductor Carrier Concentration in Semiconductors EE 332 Spring 2013 np Product – ofaw of Mass Action L Mass Action np Product – Law EE 332 Spring 2013 Intrinsic Carrier Concentration of GaAs At room temperature (T=300 K), intrinsic carrier concentration in GaAs (Eg =1.43 eV) Nc = 4.5 × 1017 cm −3 ni = Nc Nv e Nv = 8.1× 1018 cm −3 − Eg / 2 kT = 2.3 × 106 cm −3 Atom density of GaAs is 2.22 x 1022 cm-3 (Ga and As) In case majority carrier is from intrinsic carrier, the impurity of GaAs should be lower than 10-16 EE 332 Spring 2013 Intrinsic Fermi Level Intrinsic Fermi Level EE 332 Spring 2013 Example: Solving Problem Hint: EE 332 Spring 2013 Solution Solution Since B (trivalent) is a p-type dopant in Si, hence, the material will be predominantly p-type, and since NA>>ni, therefore, p0 will be approximately equal to NA, and n0 = ni2/p0 = 2.25 x 104 cm-3. EE 332 Spring 2013...
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This document was uploaded on 02/18/2014.

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