Using reflectance anisotropy spectroscopy, after identifying the main spectral lines for the InAs(001) surfaces, it was demonstrated that low-temperature (140K) oxygen adsorption proceeded in a completely different way for the As-rich and In-rich surfaces. The oxygen was chemisorbed on the In-rich (4 x 2) surface, as deduced from the disappearance, from the reflectance anisotropy spectrum, of the optical transitions due to surface dimers. The adsorbed oxygen could not be removed by annealing, even at up to 670K. On the As-rich β2 and α2 surface reconstructions, adsorption was limited to molecular physisorption: oxygen was desorbed by annealing at the significantly lower temperature of ≈300K, and only weakly perturbed the signal related to surface dimers.

Effect of Surface Reconstruction on the Low-Temperature Oxidation of InAs(100): Optical Investigations. V.L.Berkovits, N.Witkowski, Y.Borensztein, D.Paget: Physical Review B, 2001, 63[12], 121314 (4pp)