Interband optical absorption in a small-radius quantized spherical film

The electronic conditions and direct optical transitions in a semiconductor quantized spherical film under ‘strong’ quantization regime are considered when the size of the system is smaller than that of a bulk exciton. A physically adequate model is suggested that allows to find analytically the energy spectrum and wave functions of the charge carriers in the layer. In an approximation of simple non-degenerate bands, the absorption coefficient for interband and ‘intersubband’-inband transitions is found. Along with the frequency dependence, the explicit dependence of the absorption coefficient on the geometrical size of the model is revealed.