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Problem: Direct-Gap Semiconductor

        Consider a semiconductor with a direct gap of tex2html_wrap_inline6743 around tex2html_wrap_inline5643 . The valence band is described by a ``parabolic" tex2html_wrap_inline5995 with a hole mass of tex2html_wrap_inline6749 ; the conduction band is described by an electron mass of tex2html_wrap_inline6751 . Assume that in the neighborhood of tex2html_wrap_inline5643 , the electronic transition matrix element (for transitions from the valence band to the conduction band) is independent of tex2html_wrap_inline5233 , and therefore the oscillator strength is constant, tex2html_wrap_inline6757 .

Calculate the conductivity tex2html_wrap_inline6759 around tex2html_wrap_inline6761 . What happens in a one-dimensional system?

 

This document can be accessed on the World Wide Web at "http//:solidstate.physics.sunysb.edu/book/prob/ ".

Laszlo Mihaly
Thu Oct 31 13:23:11 EST 1996

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