Immediate Product after Exposing Si(111)-7x7 Surface to O2 at 300 K

Using real-time O is X-ray photoelectron spectoscopy together with Si 2p X ray photoelectron spectroscopy the oxygen bonding configurations of oxides shortly after exposing the Si(111)-7x7 surface to O-2 at 300 K are revealed. It is found that the ins structure firstly forms where one oxygen atom sits in the backbond of the silicon adatom. It is confirmed that the chemisorbed molecular oxygen the so called paul oxygen is the adsorbate on top the ins structure. It is also clarified that the ad-ins structure and the ins-tri structure where ad means an oxygen atom adsorbed onto top of the silicon adatom and tri means the interstitial oxygen atom appear after a short time. The results implying the presence of mobile O-2 on the surface were obtained (C) 2010 The Japan Society of Applied Physics