Two-dimensional TiOx nanostructures on Au(111): a scanning tunneling microscopy and spectroscopy investigation
Two-dimensional TiOx nanostructures on Au(111): a scanning tunneling microscopy and spectroscopy investigation
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Au(111) 上的二维 TiOx 纳米结构：扫描隧道显微镜和光谱研究
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
A. Bassi
中科院分区：
文献类型：
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作者：
F. Tumino;P. Carrozzo;L. Mascaretti;C. Casari;M. Passoni;S. Tosoni;C. Bottani;A. Bassi
我们研究了在Au（111）衬底上通过Ti蒸发和沉积后氧化生长氧化钛二维纳米结构。扫描隧道显微镜和光谱学（STM和STS）和低能电子衍射测量的特征在于所观察到的结构的形态，结构和电子特性。五个不同的TiOx相被确定：蜂窝状和风车状相出现作为单层膜润湿的金表面，而三角形，行和针状相的纳米晶主要生长在蜂窝状或风车状层。蜂窝结构的密度泛函理论研究支持（2 × 2）？>基于具有Ti 2 O3化学计量的Ti-O双层的结构模型。观察到的风车相演变，增加覆盖率，从单一的三角形微晶形成一个良好的有序膜形成（4 7 × 4 7）R 19.1 °？>超结构，这可以在莫尔模型内解释。通过对高分辨率STM测量结果的分析，揭示了其他三相的结构特征。STS测量结果表明，部分金属化的蜂窝和风车和半导体字符的行和三角形相。
We investigated the growth of titanium oxide two-dimensional nanostructures on Au(111), produced by Ti evaporation and post-deposition oxidation. Scanning tunneling microscopy and spectroscopy (STM and STS) and low-energy electron diffraction measurements characterized the morphological, structural and electronic properties of the observed structures. Five distinct TiOx phases were identified: the honeycomb and pinwheel phases appear as monolayer films wetting the gold surface, while nanocrystallites of the triangular, row and needle phases grow mainly over the honeycomb or pinwheel layers. Density Functional Theory investigation of the honeycomb structure supports a ( 2 × 2 ) ?> structural model based on a Ti-O bilayer having Ti2O3 stoichiometry. The pinwheel phase was observed to evolve, for increasing coverage, from single triangular crystallites to a well-ordered film forming a ( 4 7 × 4 7 ) R 19.1 ° ?> superstructure, which can be interpreted within a moiré-like model. Structural characteristics of the other three phases were disclosed from the analysis of high-resolution STM measurements. STS measurements revealed a partial metallization of honeycomb and pinwheel and a semiconducting character of row and triangular phases.