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Unformatted text preview: Lecture 8 Wednesday February 9 EE 332 Semiconductor Devices Problem Assignment Monday ! 3.1, 3.2, 3.6 Wednesday ! 3.17, 3.21 Chapter 3 Review Questions 2-8 Optical Absorption and EHP Formation Absorption of photons with energy greater than E g create electron hole pairs. eV μ m 24 . 1 λ λ υ = = = hc h E Generation and Recombination Processes Direct and Indirect Bandgaps A photon produces a vertical transition. A phonon produces a diagonal transition Direct and Indirect Emission Maximum phonon energy is less than bandgap Thus several phonons or a phonon and a photon are required to take an electron between the conduction and valance band. Write Concentrations as Departure from Equilibrium ) ( ) ( ) ( ) ( t p p t p t n n t n ∆ + = ∆ + = dt t p d dt t dp dt t n d dt t dn ) ( ) ( ) ( ) ( ∆ = ∆ = Write instantaneous concentration as the equilibrium concentration plus a small departure. The derivatives of n ( t ) and p ( t ) then become: Charge Transport in Semiconductors We have studied the drift current resulting from...
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This note was uploaded on 06/30/2010 for the course EECE 332 taught by Professor Constable during the Spring '08 term at Binghamton.
- Spring '08