STRUCTURE OF INP(001) SURFACES PREPARED BY DECAPPING AND BY ION-BOMBARDMENT AND ANNEALING

The structure of InP surfaces prepared by ion bombardment and annealin g (IBA) and by decapping of InP (001) samples grown by metal organic v apor phase epitaxy is Studied. The structural changes of the surfaces during preparation are monitored by low-energy electron diffraction an d related to the surface electronic modifications as revealed by refle ctance-anisotropy spectroscopy (RAS). For both preparation methods we find (2X4) reconstructions and almost identical RAS spectra. This find ing contrasts with previous reports usually claiming a (4X2) surface a fter IBA Auger-electron spectroscopy as well as hydrogen-adsorbate vib rations recorded with high-resolution electron-energy spectroscopy ind icate an In-rich surface stoichiometry.