The classical oscillator model and dielectric constants extracted from infrared reflectivity measurements

The theoretical foundation of the classical oscillator model for the dielectric response of doped semiconductors is reviewed and some errors from the literature are pointed out. Four different modifications of the plasma frequency are identified and their physical significance is given. The influence of the dielectric parameters on reflectivity is discussed. Large changes in the dielectric parameters extracted from experimental reflectivity measurements have been reported, when in fact inappropriate or inadequate reflectivity models have been applied.