Interface optical phonons and its ternary mixed effects in ZnS/CdxZn1-xS quantum dots

Abstract

Taking into account cadmium element concentrations, the interface optical (IO) phonons, electron-phonon couplings in ZnS/CdxZn1-xS quantum dots are investigated theoretically within the framework of macroscopical dielectric continuum model (MDCM) and modified random-element isodisplacement model (MREIM). The numerical results indicate that the cadmium element concentrations have important effects on the properties of IO phonons and electron-phonon interactions in a single ZnS/CdxZn1-xS quantum dot. The dependences between IO phonon frequencies and cadmium element concentrations are linearly decreases in high frequency range (HF-range), and are non-linearly decreases in low frequency range (LF-range). The numerical results also suggest that the dependent relations between the absolute value of electron-phonon coupling strengths and cadmium element concentration are linear relationship in high frequency range (HF-range), and are non-linear relationship in low frequency range (LF-range), especially in higher cadmium element concentration range.