Facet selective etching of Au microcrystallites

作     者：Gangaiah Mettela and Giridhar U. Kulkarni 

作者机构：Thematic Unit of Excellence on Nanochemistry and Chemistry and Physics of Materials Unit Jawaharlal Nehru Centre for AdvancedScientific Research (JNCASR) Jakkur P.O. Bangalore 560 064 India 

出 版 物：《Nano Research》 (纳米研究（英文版）)

年 卷 期：2015年第8卷第9期

页      面：2925-2934页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：Council for Scientific and Industrial Research 

主　　题：gold,microcrystallites,facet selective eapping 

摘      要：High-symmetry crystals exhibit isotropic properties. Inducing anisotropy, e.g., by facet selective etching, is considered implausible in face-centered cubic （FCC） metals, particularly gold, which, in addition to being an FCC, is noble. We report for the first time the facet selective etching of Au microcrystals obtained in the form of cuboctahedra and pentagonal rods from the thermolysis of a gold- organic precursor. The selective etching of {111} and {100} facets was achieved using a capping method in which tetraoctylammonium cations selectively cap the {111} facets while Br- ions protect the {100} facets. The exposed facets are oxidized by O2/C1-, yielding a variety of interesting geometries. The facet selective etching of the Au microcrystallites is governed only by the nature of the facets; the geometry of the microcystallite does not appear to play a significant role. The etched surfaces appear rough, but a closer examination reveals well-defined corrugations that are indexable to high hkl values. Such surfaces exhibit enhanced Raman activity.