IN-SITU OBSERVATION OF SURFACE OPTICAL ANISOTROPY ON INP, INAS, AND INSB BY CHEMICAL MODULATION SPECTROSCOPY

In situ observation of surface optical anisotropy due ro In dimers in a set of three in-based semiconductor binary compounds-InP, InAs, and InSb-grown by molecular-beam epitaxy is reported. Pie used an optical reflection technique based on the chemical modulation of the surface, that permits the measurement with light linearly polarized in one sele cted polarization, usually [110] or [1(1) over bar0$], typically paral lel to the group-III and -V dimers. Spectra for (001) surfaces in the 1-3-eV range were: obtained through this technique, and the results ar e compared to those previously obtained for a set of Ga-based binary c ompounds, GaP, GaAs and GaSb. For both sets, well-defined features for light polarized along [110] have been observed, that are attributed t o transitions between the occupied group-m dimer and the unoccupied da ngling-bond bands.