IR reflection of optical phonons in GaN/AlGaN superlattices

Abstract

We present the IR study of vibrational properties of GaN/Al 0.28 Ga 0.72 N superlattices with different thickness of superlattice layers. IR reflection spectra of the superlattices were taken at normal and off-normal incidence using p-polarised light in order to analyze optical phonons propagating both along and perpendicular to the layer surface. Optical phonon frequencies as well as thickness of the structure layers were determined from a comparison of the experimental IR reflection spectra to those calculated in the framework of the dielectric continuum model.