Woodruff School of Mechanical Engineering
Faculty Candidate Seminar
Process modeling and system design for scalable and affordable nanomanufacturing
Dr. Sourabh Saha
Lawrence Livermore National Laboratory
Wednesday, February 21, 2018 at 11:00:00 AM
MRDC Building, Room 4211
Dr. Christopher Saldana
There is a demonstrated need for scalable and affordable manufacturing of complex micro and nano-scale structures for applications such as photonics-based sensing, mechanical metamaterials, electrochemical energy storage, and fluidics-based medical diagnostics. Although high-rate patterning of such structures is feasible via replication of templates/stamps, overall scalability is limited by expensive and slow template generation processes. Here, I will present case studies for three different pattern generation techniques to demonstrate how I utilize process modeling and system design to quantify and overcome scalability versus performance tradeoffs. First, I will present process modeling of dip pen nanolithography which is a tip-based nanofabrication technique capable of writing <50 nm features. I will demonstrate how simplified yet physically accurate models can generate valuable process knowledge that cannot be obtained through experimentation alone. Next, I will present my work on predictive design and fabrication of multi-period hierarchical structures via wrinkling/buckling of thin films – an inherently scalable mechanical self-organization technique. I will demonstrate how I have utilized custom-made experimental and computational tools to systematically study and increase the complexity of patterns generated via wrinkling. Finally, I will present my recent work on two-photon lithography (TPL). TPL is a point-scanning additive manufacturing technique capable of generating 3D structures with <150 nm features. Past attempts to parallelize TPL have failed to preserve the ability to fabricate arbitrarily complex 3D structures. At LLNL, we have successfully overcome this tradeoff by harnessing the temporal properties of ultrafast lasers to achieve at least two orders of magnitude increase in the curing rate without sacrificing the submicron feature resolution.
Sourabh Saha is an R&D Engineer at Lawrence Livermore National Laboratory. He previously held a postdoctoral position at LLNL from 2015 to 2017. He received his PhD in Mechanical Engineering from MIT in 2014 and his Bachelors and Masters in Mechanical Engineering from IIT Kanpur, India in 2008. His research is in the area of scalable and affordable nanomanufacturing with the goal of breaking traditional engineering tradeoffs through process and system innovations. His wrinkling research was recognized at ASME IMECE 2013 conference with a best poster award and at MIT he was a recipient of the Pappalardo graduate fellowship and the Martin family fellowship for sustainability. At LLNL, he is leading a Laboratory Directed Research & Development (LDRD) project to scale up two-photon lithography. He holds 3 issued/allowed patents on wrinkling and is licensed in California as a Professional Engineer.
Refreshments will be served.