Precious Cantú
École Polytechnique Fédérale de Lausanne (EPFL)
precious.cantu@epfl.ch
Bio
Dr. Precious Cantú is a Postdoctoral Researcher in the Materials Science and Engineering Department at École Polytechnique Fédérale de Lausanne (EPFL), where she works with Professor Francesco Stellacci in the Supramolecular Nanomaterials and Interfaces Laboratory. She recently received her Ph.D. in Electrical Engineering from the University of Utah, advised by Prof. Rajesh Menon. Her research area of interest is Optics and Nanofabrication, with a specific focus on extending the spatial resolution of optics to the nanoscale. Her Ph.D. dissertation focused on developing a novel nanopatterning technique using wavelength-selective small molecules.
She is the recipient of the National Science Foundation Graduate Research Fellowship (NSF GRFP), University of Utah Nanotechnology Training Fellowship, Global Entrepreneurship Monitor Consortium (GEM) Fellowship, More Graduate Education at Mountain States Alliance (MGE/MSA) Fellowship, and The Fulbright U.S. Scholars Fellowship.
Patterning via Optical Saturable Transitions
Patterning via Optical Saturable Transitions
For the past 40 years, optical lithography has been the patterning workhorse for the semiconductor industry. However, as integrated circuits have become more and more complex, and as device geometries shrink, more innovative methods are required to meet these needs. In the far-field, the smallest feature that can be generated with light is limited to approximately half the wavelength. This, so called far-field diffraction limit or the Abbe limit (after Prof. Ernst Abbe who first recognized this), effectively prevents the use of long-wavelength photons >300nm from patterning nanostructures <100nm. Even with a 193nm laser source and extremely complicated processing, patterns below ~20nm are incredibly challenging to create. Sources with even shorter wavelengths can potentially be used. However, these tend be much more expensive and of much lower brightness, which in turn limits their patterning speed. Multi-photon reactions have been proposed to overcome the diffraction limit. However, these require very large intensities for modest gain in resolution. Moreover, the large intensities make it difficult to parallelize, thus limiting the patterning speed. In this dissertation, a novel nanopatterning technique using wavelength-selective small molecules that undergo single-photon reactions, enabling rapid top-down nanopatterning over large areas at low-light intensities, thereby allowing for the circumvention of the far-field diffraction barrier is developed and experimentally verified. This approach, which I refer to as Patterning via Optical Saturable Transitions (POST) has the potential for massive parallelism, enabling the creation of nanostructures and devices at a speed far surpassing what is currently possible with conventional optical lithographic techniques. The fundamental understanding of this technique goes beyond optical lithography in the semiconductor industry and is applicable to any area that requires the rapid patterning of large-area two or three-dimensional complex geometries.