New experimental results were reported by researchers at the Korea Research Institute of Standards and Science. They succeeded in fabricating and assembling freestanding nanogears with one center hole surrounded by six teeth. Nanogears with an overall size of less than 500 nm and a thickness of 60–70 nm were obtained by selectively etching the chemically synthesized single crystalline gold nanoplates using a Ga+ focused ion beam under real-time monitoring. The nanogears were easily flipped, picked up, translated and rotated after removing the underlying SiO2 layer slightly in order to weaken the bond between them and the substrate.
The nanogears were assembled tooth to tooth without damage by using an atomic force microscope (AFM) in contact mode. The researchers also demonstrated that blunt AFM tips on stiff cantilevers are effective for the non-destructive manipulation of ductile and flat nano-objects that like having large contact areas with the substrate. This is the first step toward the realization of sophisticated nanomachines designed to perform specific tasks. The future challenges lie mostly in the study and development of efficient 3D assembling and driving techniques