1. Sustainable Energy Technologies Department

    "Graphene Synthesis, Fabrication and Applications in Optical Detection"

    Presented by Isaac Ruiz, Sandia National Laboratory

    Wednesday, January 17, 2018, 11 am
    Bldg. 734 (ISB) 2nd Floor Seminar Room 201

    Hosted by: Pat Looney

    There is considerable promise in developing integrated graphene devices for various optical and electrical applications. Being able to reliably fabricate devices is absolutely vital for the success and proliferation of graphene and other 2 dimensional materials; however, there are numerous challenges that need to be addressed, beginning with material synthesis and continuing all the way through fabrication and device characterization. In this presentation an overview of my work will be presented, starting with my Ph.D. thesis work in fabricating high quality monolayer graphene films by chemical vapor deposition (CVD). Common particle contamination occurring from the CVD growth of graphene in quartz tubes is examined, identified and eliminated resulting in pristine CVD films. Next the copper surface morphology effects on CVD graphene growth are presented and a method for rapid (sub 1 min growth time) high quality graphene synthesis is demonstrated. More recent work involving graphene device fabrication and integration conducted at Sandia National Laboratories is shown. Some of the common pitfalls of graphene integration are presented along with solutions, which have increased our yield and reliability greatly in just 2 years. Finally, I demonstrate 2 applications that we have been able to integrate with great success. The control of the visibility of graphene films encapsulated in different dielectrics and dielectric thicknesses is shown and a model is developed which is in good agreement with experimentally measured values. To conclude I give an overview of SNL's latest graphene based optical detector, the deeply depleted graphene/oxide/semiconductor junction detector (D2GOS). We demonstrate its high responsivity (~2800 A/W) in the visible wavelength range and its potential to be used in other optical frequencies.