Atomically flat gold on elastomeric substrate

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Fabricating smooth gold films is crucial for applications in electronics and photonics.
• Existing methods often struggle to achieve both smoothness and large grain size on flexible substrates.

Purpose of the Study:

• To develop a procedure for fabricating extremely smooth gold (Au) films on elastomeric poly(dimethylsiloxane) (PDMS) substrates.
• To optimize the growth and transfer process for high-quality Au films with minimal surface roughness and large grain size.

Main Methods:

• Utilized silicon wafers with native oxide and release layers as templates for thermally evaporated Au films at 300°C.
• Transferred Au films (up to 200 nm thick) onto surface-functionalized PDMS using a (3-mercaptopropyl)trimethoxysilane adhesion layer.
• Characterized film smoothness and morphology using Atomic Force Microscopy (AFM).

Main Results:

• Achieved extremely smooth Au films with root-mean-square (rms) roughness of 2.5–4 angstroms.
• Observed large, flat crystalline grains exceeding 500 nm in size for thicker films.
• Thinner films (down to 20 nm) exhibited comparable smoothness but reduced crystalline morphology.

Conclusions:

• The optimized procedure effectively produces ultra-smooth, crystalline gold films on PDMS substrates.
• The templated growth on Si wafers followed by transfer is a viable method for high-quality thin film fabrication.
• The results offer a pathway for creating advanced functional materials for flexible electronics and sensors.