Unformatted text preview: condition for equilibrium between electrons and holes is: μ e + μ h = . Assume that the electrons and holes each form an ideal gas and that the conduction band is separated from the valance band by an energy gap E g . (a) Show that the density of electrons in the conduction band is given by: n e = 2 ± τ √ m e m h 2 π ¯ h 2 ² 3 / 2 exp ±E g 2 τ ² , where m e and m h are the effective masses of the electrons and holes. (b) Use your result from part (a) to show that: μ e = E g 2 + 3 τ 4 ln ± m h m e ² . (c) Now consider a semiconductor that also contains a density n D of donors that each contribute one electron to the conduction band. Show that the electron density is now: n e = n D 2 + r n 2 D 4 + n 2 e . 1...
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 Fall '06
 StevenG.Louie
 Physics, Electron, Energy, Fundamental physics concepts, Energy density, 1022 cm

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