Elucidating the charge state of an Au nanocluster on the oxidized/reduced rutile TiO2 (110) surface using non-contact atomic force microscopy and Kelvin probe force microscopy

Yuuki Adachi; Huan Fei Wen; Quanzhen Zhang; Masato Miyazaki; Yasuhiro Sugawara; Yan Jun Li

doi:10.1039/c9na00776h

Elucidating the charge state of an Au nanocluster on the oxidized/reduced rutile TiO₂ (110) surface using non-contact atomic force microscopy and Kelvin probe force microscopy

Nanoscale Adv. 2020 Mar 25;2(6):2371-2375. doi: 10.1039/c9na00776h. eCollection 2020 Jun 17.

Authors

Yuuki Adachi¹, Huan Fei Wen², Quanzhen Zhang¹, Masato Miyazaki¹, Yasuhiro Sugawara¹, Yan Jun Li¹

Affiliations

¹ Department of Applied Physics, Graduate School of Engineering, Osaka University 2-1 Yamadaoka Suita Osaka 565-0871 Japan liyanjun@ap.eng.osaka-u.ac.jp.
² Key Laboratory of Instrumentation Science and Dynamic Measurement, School of Instrument and Electronics, North University of China Taiyuan Shanxi 030051 P. R. China.

Abstract

The charge state of Au nanoclusters on oxidized/reduced rutile TiO₂ (110) surfaces were investigated by a combination of non-contact atomic force microscopy and Kelvin probe force microscopy at 78 K under ultra-high vacuum. We found that the Au nanoclusters supported on oxidized/reduced surfaces had a relatively positive/negative charge state, respectively, compared with the substrate. In addition, the distance dependence of LCPD verified the contrast observed in the KPFM images. The physical background of charge transfer observation can be explained by the model of charge attachment/detachment from multiple oxygen vacancies/adatoms surrounding Au nanoclusters. These results suggest that the electronic properties of the Au nanoclusters are dramatically influenced by the condition of the support used.