题目：

In situ study of the electronic structure of atomic layer deposited oxide ultrathin films upon oxygen adsorption using ambient pressure XPS

作者：

Bao-Hua Mao,^abc Ethan Crumlin,^c Eric C. Tyo,^d Michael J. Pellin,^d Stefan Vajda,^defg Yimin Li,*^bh Sui-Dong Wang*^a and Zhi Liu*^bch

单位：

^aInstitute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, People's Republic of China.

^bState Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China.

^cAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

^dMaterials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA

^eNanoscience & Technology Division, Argonne National Laboratory, Argonne, Illinois 60439, USA

^fDepartment of Chemical and Environmental Engineering, School of Engineering & Applied Science, Yale University, New Haven, Connecticut 06520, USA

^gInstitute of Molecular Engineering, The University of Chicago, 5747 South Ellis Avenue, Chicago, IL, 60637, USA

^hSchool of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China

摘要：

In this work, ambient pressure X-ray photoelectron spectroscopy (APXPS) was used to investigate the effect of oxygen adsorption on the band bending and electron affinity of Al₂O₃, ZnO and TiO₂ ultrathin films (∼1 nm in thickness) deposited on a Si substrate by atomic layer deposition (ALD). Upon exposure to oxygen at room temperature (RT), upward band bending was observed on all three samples, and a decrease in electron affinity was observed on Al₂O₃ and ZnO ultrathin films at RT. At 80 °C, the magnitude of the upward band bending decreased, and the change in the electron affinity vanished. These results indicate the existence of two surface oxygen species: a negatively charged species that is strongly adsorbed and responsible for the observed upward band bending, and a weakly adsorbed species that is polarized, lowering the electron affinity. Based on the extent of upward band bending on the three samples, the surface coverage of the strongly adsorbed species exhibits the following order: Al₂O₃ > ZnO > TiO₂. This finding is in stark contrast to the trend expected on the surface of these bulk oxides, and highlights the unique surface activity of ultrathin oxide films with important implications, for example, in oxidation reactions taking place on these films or in catalyst systems where such oxides are used as a support material.

影响因子：

5.287

分区情况：

2区

链接：

http://pubs.rsc.org/-/content/articlehtml/2016/cy/c6cy00575f

责任编辑：向丹婷 联系方式：dtxiang@suda.edu.cn

（责任编辑：金晓瑜 联系方式：xyjin@suda.edu.cn）