High‐Throughput Growth of Microscale Gold Bicrystals for Single‐Grain‐Boundary Studies

Abstract

The study of grain boundaries is the foundation to understanding many of the intrinsic physical properties of bulk metals. Here, the preparation of microscale thin‐film gold bicrystals, using rapid melt growth, is presented as a model system for studies of single grain boundaries. This material platform utilizes standard fabrication tools and supports the high‐yield growth of thousands of bicrystals per wafer, each containing a grain boundary with a unique <111> tilt character. The crystal growth dynamics of the gold grains in each bicrystal are mediated by platinum gradients, which originate from the gold–platinum seeds responsible for gold crystal nucleation. This crystallization mechanism leads to a decoupling between crystal nucleation and crystal growth, and it ensures that the grain boundaries form at the middle of the gold microstructures and possess a uniform distribution of misorientation angles. It is envisioned that these bicrystals will enable the systematic study of the electrical, optical, chemical, thermal, and mechanical properties of individual grain boundary types.

Influence of displacement constraints to the surface reconstruction of stressed bicrystal thin films

“…Since the material system investigated here comprised of a single grain boundary, it is hard to compare the simulation results with an experimental work. However, with the development of novel procedures to produce thin film bicrystals in micro and nanoscale dimensions [31] and advanced materialographic sample preparation methods [32] it will be possible to validate the phenomenon presented herewith.…”

Detection of Trace Impurity Gradients in Noble Metals by the Photothermoelectric Effect

“…The devices studied in this work are single-crystal 17 and bicrystal 18 gold wires that are prepared on a thermally oxidized Si substrate to provide thermal and electrical isolation and fabricated using the metal-on-insulator rapid melt growth technique. In this growth process, a polycrystalline gold stripe and polycrystalline platinum seed are annealed at a high temperature above gold's melting point of 1064 °C.…”

“…Samples were grown according to previously published methods. , 300 nm of thermal SiO 2 was grown on Si substrates, followed by 30 nm of electron beam-evaporated Pt with a 2 nm Ti adhesion layer. 10 μm by 10 μm seeds were defined using photolithography followed by metal liftoff.…”