Characterizing TiO2(110) surface states by their work function

被引：95

作者：

Borodin, Andriy ^{[1
]}

Reichling, Michael ^{[1
]}

机构：

[1] Univ Osnabruck, Fachbereich Phys, D-49069 Osnabruck, Germany

来源：

PHYSICAL CHEMISTRY CHEMICAL PHYSICS | 2011年 / 13卷 / 34期

关键词：

IMPACT ELECTRON-SPECTROSCOPY; RUTILE TIO2(110); ATOMIC-STRUCTURE; TIO2; ADSORPTION; HYDROGEN; GAP; H2O; STM; O-2;

D O I：

10.1039/c0cp02835e

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The unreconstructed TiO2(110) surface is prepared in well-defined states having different characteristic stoichiometries, namely reduced (r-TiO2, 6 to 9% surface vacancies), hydroxylated (h-TiO2, vacancies filled with OH), oxygen covered (ox-TiO2, oxygen adatoms on a stoichiometric surface) and quasi-stoichiometric (qs-TiO2, a stoichiometric surface with very few defects). The electronic structure and work function of these surfaces and transition states between them are investigated by ultraviolet photoelectron spectroscopy (UPS) and metastable impact electron spectroscopy (MIES). The character of the surface is associated with a specific value of the work function that varies from 4.9 eV for h-TiO2, 5.2 eV for r-TiO2, 5.35 eV for ox-TiO2 to 5.5 eV for qs-TiO2. We establish the method for an unambiguous characterization of TiO2(110) surface states solely based on the secondary electron emission characteristics. This is facilitated by analysing a weak electron emission below the nominal work function energy. The emission in the low energy cut-off region appears correlated with band gap emission found in UPS spectra and is attributed to localised electron emission through Ti3+(3d) states.

引用

页码：15442 / 15447

页数：6

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