Publishing in International Journal of Extreme Manufacturing , Prof. Yanquan Geng's team at Harbin Institute of Technology has devised a way to carve variable-depth, three-dimensional trenches into gallium antimonide, a notably brittle semiconductor, using a microscopic tip vibrating thousands of times per second.
The Existing Industry Problem
Single-crystal gallium antimonide (GaSb) boasts outstanding electron mobility, making it a highly attractive material for advanced infrared detectors and solar cells. However, the material is extremely brittle.
Traditional atomic force microscopy (AFM) machining typically drags a hard tip across a surface to scratch out a channel in a single pass. This standard approach restricts the channel's geometry to the exact shape of the probe and often leaves a thick layer of damaged, amorphous material that ruins the semiconductor's vital electrical properties. Manufacturers have lacked a reliable method to precisely sculpt complex 3D topographies into these high-performance, fragile crystals.
The Breakthrough and Performance
To solve this, Prof. Geng's team transformed the AFM probe into a high-frequency nanomilling tool. By rapidly vibrating the probe up to 5,000 times per second (5,000 hertz) while simultaneously rotating the sample, the team successfully sculpted intricate 3D nanogrooves with precisely controlled depths and widths.
Crucially, dialing up the vibration frequency drastically improved the crystal's structural integrity. When the milling frequency was increased from 500 hertz to 5,000 hertz, the thickness of the damaged, amorphous GaSb layer at the bottom of the groove significantly decreased.
The Mechanism
The physics driving this improvement relies on rapid strain hardening. At 5,000 hertz, the rapid and shallow impacts force the crystal's atomic lattice to form a dense tangle of dislocations near the surface. These tangled dislocations act as a structural barrier that prevents the amorphous damage from diffusing deeper into the material.
The process is akin to a sculptor using rapid and shallow taps with a chisel to remove tiny flakes of ice smoothly, rather than using deep, sustained gouges that would cause unpredictable cracks to shatter the underlying block.
The Manufacturing Impact and Future Outlook
To prove the practical viability of these pristine 3D nanogrooves, Prof. Geng's team built a lab-scale nanofluidic memristor - a liquid-based chip that regulates ion flow to "remember" electrical states, much like a biological synapse.
By utilizing newly milled variable-depth channels with a periodic length of 9.5 micrometers, the asymmetrical geometry forced ions to flow unevenly. The negatively charged surfaces of the grooves repelled anions and attracted cations, creating a non-uniform electric field that amplified the contrast between high- and low-conductance states. This asymmetry enabled the device to achieve a highly efficient electrical switching ratio of 1.77.
While currently a laboratory prototype, scaling up this variable-depth milling technique offers a low-cost, highly-controllable strategy for the factory-floor processing of soft, brittle materials. This high-frequency nanomilling blueprint paves the way for the continuous development of more complex, brain-like nanofluidic circuits and next-generation optoelectronic devices.
International Journal of Extreme Manufacturing (IJEM, IF: 21.3 ) is dedicated to publishing the best advanced manufacturing research with extreme dimensions to address both the fundamental scientific challenges and significant engineering needs.
Visit our webpage , like us on Facebook , and follow us on Twitter and LinkedIn .
International Journal of Extreme Manufacturing
Modelling and experimental study of nanomilling 3D nanogrooves on GaSb surfaces
13-Feb-2026