Microwave-radiation-induced structural transformations in homo- and heterogeneous GaAs-based systems

The effect of microwave irradiation ($f$ = 2.45 GHz, 1.5 W/cm$^2$, $t$ = 1 or 2 min) on the reflectance and photoluminescence spectra of the epitaxial $n$–$n^+$–GaAs and Au–$n$–$n^+$–GaAs structures is studied. Short-term microwave irradiation is shown to cause long-term nonmonotonic changes in the spectral characteristics, which can result from the structure modification of the near-surface regions in the epitaxial films. The long-term changes of the optical spectra of the structures that occur after microwave irradiation are explained.