Estimation of plasma frequency from IR reflectivity in doped GaAs

Abstract

The influence of the phonon-plasmon coupling on the IR reflectivity spectra of doped GaAs is examined for the range of plasma frequencies which are close to the optical phonon frequencies. An analytic expression for the plasma frequency in terms of the frequencies of the reflectivity minima, which requires knowledge of the dielectric constant at the reflectivity minima and the carrier lifetime, is obtained. Empirical relations are suggested to estimate the required dielectric constant. Lifetime is estimated by a graphical method. These relations are used to estimate the plasma frequencies from the reported reflectivity spectra of doped GaAs samples. © 1984.