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  • MHI Nano Science & Technology Seminar - Haozhe "Harry" Wang, Wednesday, January 18th at 10:30am in EEB 132

    Wed, Jan 18, 2023 @ 10:30 AM - 12:00 PM

    Ming Hsieh Department of Electrical and Computer Engineering

    Conferences, Lectures, & Seminars

    Speaker: Haozhe \"Harry\" Wang, California Institute of Technology

    Talk Title: Scalable Manufacturing for Quantum Materials in Angstrom Precision

    Series: Nano Science & Technology

    Abstract: The figures of merit of quantum devices based on semiconductor and quantum materials are increasingly limited by imperfections introduced in nanofabrication. Further advances in capabilities demand both additive and subtractive manufacturing methods with vastly improved precision compared to that of typical approaches. In this talk, I will describe our development of additive manufacturing of bilayer graphene leveraging chemical vapor deposition and \'smart\' processes. While the number of exciting quantum effects observed in bilayer graphene increases, a significant gap persists in transforming these discoveries into practical applications, owing to the small-scale samples obtained via top-down approaches. We realized a layer-by-layer (that is, Frank-van der Merwe) growth mode in large-scale bilayer graphene, with no island impurities, which is unprecedented in any van der Waals-stacked materials. Machine learning is adopted to assist spectroscopy, enabling the \'smart\' characterization following the
    chemical vapor deposition. After growth, a transfer is necessary to move bilayer graphene from the growth substrate to a destination substrate with a mandatory sacrificial support layer. This process induces residuals, wrinkles, and cracks, thus deteriorating 2D materials from their intrinsic properties. We utilized the Marangoni effect, also known as the \'tears of wine\', to enable \'smart\' transfer by building a surface tension gradient in transfer liquids. We demonstrate our autonomous Marangoni-flow transfer technique can transfer bilayer graphene without a support layer, resulting in residue-free bilayer graphene. In addition, I will discuss our recent progress in the subtractive manufacturing of semiconductors and quantum hardware in Angstrom precision using the atomic layer etching technique.

    Biography: Dr. Haozhe Wang is currently KNI Prize Postdoctoral Fellow at the
    California Institute of Technology (Caltech). He is working on atomic layer etching (ALE) technology for quantum materials to remedy surface imperfections in electronic and optical quantum devices. Before joining Caltech, he obtained his Ph.D. in Electrical Engineering from the Massachusetts Institute of Technology (MIT) in 2020, working on the scalable synthesis and application of quantum materials.

    Host: J Yang, H Wang, C Zhou, S Cronin, W Wu

    More Information: Haozhe_0118.pdf

    Location: Hughes Aircraft Electrical Engineering Center (EEB) - 132

    Audiences: Everyone Is Invited

    Contact: Marilyn Poplawski


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