Photon-stimulated desorption study of the NO/Si(111) surface

摘要

We have investigated the photon stimulated desorption (PSD) from the NO adsorbed Si(111) surface at 90 K. N~+, NO~+, O_2~+ and N_2O~(2+) were observed for the first time. As for N~+, we have found two TOF peaks which correspond to different kinetic energies. Comparing the photon energy dependence of the PSD experiment with the UPS spectra, we have found that the desorption of N~+ takes place from the molecularly adsorbed NO by the excitation of the 3σ molecular orbital (mainly O 2s). This result suggests that N~+ ions desorb, with the mechanism of KF model, from the NO molecules which are chemisorbed with the O atoms bonded to the surface Si atoms.