Interface roughness in semiconductor superlattices markedly affects the extent of phonon confinement and this, in turn, affects the frequencies of confined optical phonon modes. It has recently been shown [1,2] that measurements of these confined mode frequencies by Raman and far infrared spectroscopy can be used, in conjunction with a linear chain model which has been extended from Chang and Mitra's modified random element isodisplacement model [3] to incorporate interface roughness, to give a quantitative measure of interface broadening.
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