Atomic Resolution Imaging and Quantification of Chemical Functionality of Surfaces

Schwarz, Udo¹ 

[1] Yale University

关键词: Surface Catalysis;    Chemical Imaging;   

DOI  :  10.2172/1165223
RP-ID  :  DOE-YALE-15834-1
PID  :  OSTI ID: 1165223

学科分类：纳米科学和纳米技术

美国|英语

来源: SciTech Connect

【 摘 要 】

The work carried out from 2006-2014 under DoE support was targeted at developing new approaches to the atomic-scale characterization of surfaces that include species-selective imaging and an ability to quantify chemical surface interactions with site-specific accuracy. The newly established methods were subsequently applied to gain insight into the local chemical interactions that govern the catalytic properties of model catalysts of interest to DoE. The foundation of our work was the development of three-dimensional atomic force microscopy (3D-AFM), a new measurement mode that allows the mapping of the complete surface force and energy fields with picometer resolution in space (x, y, and z) and piconewton/millielectron volts in force/energy. From this experimental platform, we further expanded by adding the simultaneous recording of tunneling current (3D-AFM/STM) using chemically well-defined tips. Through comparison with simulations, we were able to achieve precise quantification and assignment of local chemical interactions to exact positions within the lattice. During the course of the project, the novel techniques were applied to surface-oxidized copper, titanium dioxide, and silicon oxide. On these materials, defect-induced changes to the chemical surface reactivity and electronic charge density were characterized with site-specific accuracy.