Epitaxial Growth of Nanostructured Gold Films on Germanium via Galvanic Displacement

摘要

This work focuses on the synthesis and characterization of gold films grown via galvanic displacement on Get I I I) substrates. The synthetic approach uses galvanic displacement, a type of electroless deposition that takes place in an efficient manner under aqueous, room temperature conditions. Investigations involving X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques were performed to study the crystallinity and orientation of the resulting gold-on-germanium films. A profound effect of HF(aq) concentration was noted, and although the SEM images did not show significant differences in the resulting gold films, a host of X-ray diffraction studies demonstrated that higher concentrations of HF(aq) led to epitaxial gold-on-germanium. whereas in the absence of HF(aq), lower degrees of order (fiber texture) resulted. Cross-sectional nanobeam diffraction analyses of the Au-Ge interface confirmed the epitaxial nature of the gold-on-germanium film. This epitaxial behavior can be attributed to the simultaneous etching of the germanium oxides, formed during the galvanic displacement process, in the presence of HF, High-resolution TEM analyses showed the coincident site lattice (CSU interface of gold-on-germanium. which results in a small 3.8% lattice mismatch due to the coincidence of four gold lattices with three of germanium.