Close-space sublimation of single-crystal metal films

Cost-effective, versatile, and rapid deposition of single-crystal metal films is crucial to a wide spectrum of applications ranging from catalysis, plasmonics, electrochemistry, and optoelectronics to templating, epitaxial substrates, and integrated nanomanufacturing. High crystal quality typically implies low growth rates, which makes it challenging to achieve thicknesses in excess of 1 µm with conventional approaches. We show facile close-space sublimation of epitaxial single-crystal Au, Ag, and Cu films on MgO substrates. We demonstrate 10 μm thickness in less than 1 h while maintaining sub-5 nm rms surface roughness for a range of low- and high-index crystal film orientations. We show that the results can be captured by a simple model based on “line-of-sight” sublimation, which serves as a predictive tool and provides a basis to discuss broader potential as well as the limitations of this approach.