Reflectance anisotropy spectra for the transition from the P-rich to the In-rich surface reconstruction of InP(100)

Reflectance anisotropy (RA) spectra of InP(100) surfaces were taken either in the MOCVD environment or, after contamination-free transfer to ultra-hig h vacuum (UHV), in UHV down to 20 K. They were correlated with photoemissio n and Auger electron spectroscopy measurements to investigate the transitio n from the P-rich to the In-rich surface reconstruction. The strongest surf ace stoichiometry-induced changes were found in the RA-spectra at around 3 eV photon energy, i.e. in the range of the surface-modified bulk E-1 transi tion. At around 1.8 eV, the main peak of a pronounced surface transition wa s recorded with equal magnitude and sign for the P-rich and for the In-rich surface reconstruction. Two different specific RA-spectra measured with th e highest peaks are postulated here to indicate the ordered P-rich and orde red In-rich surface reconstruction, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.