Making many tiny things
The strategy works for ceramics, polymers, metals, semiconductors, and other materials while still maintaining fine feature sizes. This technique could enable nanofabrication across different classes of materials.
Professor Shih-Chi Chen of the Chinese University of Hong Kong led the team which conducted the research. Professor Zhao Yongxin from Carnegie Mellon University and Professor Zhao Ni from the CUHK Department of Electronic Engineering contributed.
the team developed a general strategy for fabricating 3D nanostructures with a library of materials including metals, metal alloys, 2D materials, oxides, diamond, upconversion materials, semiconductors, polymers, biomaterials, molecular crystals and inks. In their research, hydrogels patterned by femtosecond light sheets were used as templates that allow for direct assembly of materials to form designed nanostructures. By fine-tuning the exposure strategy, the features of the patterned gel and the kinetic effects, the team made 2D and 3D structures of 20- to 200-nm resolution.
To demonstrate the capabilities of the new method, the team fabricated nanodevices including encrypted optical storage, diffractive optical elements and microelectrodes, to showcase the precision and the designed functions. The optical storage device set a new record for storage density (1.14 petabit/cm3, approximately three orders of magnitude higher than the previous record), and simultaneously set a new record for data-writing speed (84 Mbit/s), owing to the high-speed nature of the femtosecond projection method. The method points towards a systematic solution for nanofabrication across different classes of materials and opens up further possibilities for the design of nanodevices. The findings were published in Science.