Isoelectronic Impurities in Semiconductors
The term “Isoelectronic Impurity” is used to denote an impurity center in a crystal arising when an atom from the same column of the periodic table as one of the constituents of the host crystal substitutes for that constituent. Isoelectronic substitutions in certain wideband gap semiconductors have a profound effect on the optical properties of the materials for photon energies in the vicinity of the band gap. In particular, the impurity systems GaP:N, GaP:Bi, and ZnTe:0 exhibit sharp absorption lines and CdS:Te exhibits an absorption band lying within the band gaps of the pure crystals.1,2,3,4 These lines can be attributed to exciton bound states at the impurities.
KeywordsBloch Function Free Hole Wannier Function Bound State Energy Localize Exciton
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