Double reflection dips from grating ruled semiconductors

The double reflectivity dips, previously observed by Fischer et al. and Anderson et al., which appeared in the reflection spectra of grating surfaces on, the Te‐doped semiconductors GaAs and InSb around both the plasmon and phonon frequencies have been measured in more detail. In the plasmon region, several possible explanations of the phenomenon are discussed, but the favored explanation involves surface damage. A simple two‐region reflectivity equation checked with a rigorous grating theory is proposed and is shown to fit the data well.