UC San Diego

Graphene, a 2D allotrope of carbon, is a newly discovered material that possesses mechanical and electronic properties that are very appealing to multiple engineering applications. More than 9000 patents have been filed to date covering technologies that

utilize graphene, yet only a small number of those are being realized in practice due to the high cost of graphene and limited developed processes associated with its fabrication and integration on any meaningful scale (synthesis, transfer, patterning, packaging, etc.,) The following dissertation presents several solutions to the existing problems in industrializing graphene. In particular, Chapter 1 of the dissertation is a general overview of the currently discovered methods (including the one developed by the author) of non-destructive transfer of large-area graphene from synthesis substrates onto the final application substrate. Chapter 2 is devoted to a detailed coverage of the process (MAE: Metal-Assisted Exfoliation [of graphene]) developed by the author that addresses the issue of industrial scale transfer of graphene. The described process can potentially significantly increase the yields of the industrial production of graphene while drastically reducing the environmental impact of such operation. It also offers the underlying principle for several specific applications described in Chapters 3 and 4. Specifically, Chapter 3 describes the use of MAE in conjunction with nanoskiving (use of an ultramicrotome) to generate the smallest possible separations between metallic nanowires using the thickness of graphene. Such gold/graphene/gold nanowire composites could be used in molecular electronics, nano-photonics, or as described in the chapter as SERS substrates for molecular detection. Chapter 4 is devoted to several best-in-class specific sensing applications developed by the author where graphene is a functional component as well as a synthetic substrate. The multi-modal sensors composed of graphene and noble metal nanoislands (NI) demonstrated outstanding piezo-resistive properties and allowed the detection of mechanical strains as low as 0.001% while having the dynamic range of at least 5 orders of magnitude. The chapter describes the use of these sensors in health monitoring, bio-sensing, and chemical sensing applications. Appendix A and B, in their turn, cover in detail the experimental procedures used in Chapters 3 and 4 respectively.