Multi-Channel Exploration of O Adatom on TiO(2)(110) Surface by Scanning Probe Microscopy

We studied the O(2) dissociated state under the different O(2) exposed temperatures with atomic resolution by scanning probe microscopy (SPM) and imaged the O adatom by simultaneous atomic force microscopy (AFM)/scanning tunneling microscopy (STM). The effect of AFM operation mode on O adatom contrast was investigated, and the interaction of O adatom and the subsurface defect was observed by AFM/STM. Multi-channel exploration was performed to investigate the charge transfer between the adsorbed O and the TiO(2)(110) by obtaining the frequency shift, tunneling current and local contact potential difference at an atomic scale. The tunneling current image showed the difference of the tunneling possibility on the single O adatom and paired O adatoms, and the local contact potential difference distribution of the O-TiO(2)(110) surface institutively revealed the charge transfer from TiO(2)(110) surface to O adatom. The experimental results are expected to be helpful in investigating surface/interface properties by SPM.