Electron dynamics of tip-tunable oxygen species on TiO2 surface

Yuuki Adachi, Ján Brndiar, Huan Fei Wen, Quanzhen Zhang, Masato Miyazaki, Sourbh Thakur, Yasuhiro Sugawara, Hongqian Sang, Yan Jun Li*, Ivan Štich, Lev Kantorovich

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


The redox states of oxygen species on the surface of TiO2 can be altered by electron tunneling by varying the applied bias voltage of an atomic force microscope tip. However, tunneling is stochastic in nature and typically requires ultra-low temperatures to obtain statistically significant data. Here, we use a highly sensitive fast atomic force microscopy setup to study redox transitions of oxygen atoms on a TiO2 surface, in the form of reactive oxygen species and single-atom quantum dots, at 78 K. The fast and highly sensitive nature of our experimental setup enables a statistically necessary amount of data to be collected without having to resort to ultra-low temperatures. This enabled us to study multiple dots and provide insight into the electronic structure and correlation between the oxygen species, which are inaccessible by standard atomic force microscopy. We show that single-atom quantum dots exist in two charge states with drastically different conductance, with one being conducting and the other non-conducting.

Original languageEnglish
Article number71
JournalCommunications Materials
Issue number1
Early online date1 Jul 2021
Publication statusPublished - Dec 2021


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