Ferreira, Azeredo co-publish in PNAS
MechSE professor Placid Ferreira and three-time alumnus Bruno Azeredo (BSEM ’10, MSTAM ’14, PhDME ’17) co-authored a paper published May 9 in the Proceedings of the National Academy of Sciences (PNAS) of the United States of America. The paper introduces electrochemical nanoimprinting as a new, low-cost method for large-scale production of single-crystal semiconductors, such as silicon.
“We went on a journey to imprint semiconductors, particularly silicon, without the use of combined heating and imprinting,” said Azeredo, now an engineering faculty member at Arizona State University, in an interview published on the ASU website. “We found it could be done with electrochemistry, and we called it electrochemical nanoimprinting (Mac-Imprint).”
The paper’s significance statement said: “The indirect nature of existing parallel micromachining strategies that combine sacrificial templates with top-down processes to etch 3D micro- and nanostructures inherently produces poor out-of-plane patterning fidelity. Here, the patterning fidelity of our process is measured for microscale curvilinear 3D objects to be less than 20 nm in rms averaged over features as wide as 10 µm. These results are attributed to increased pathways for diffusion, which increase the kinetics of the anodic reaction. Using this approach, arrays of nanotextured silicon lenses are deterministically imprinted to illustrate Mac-Imprint’s ability to directly pattern hierarchical micro- and nanostructures and enable fabrication of biomimetic optical designs on silicon.”