Abstract:

My research addresses fundamental challenges in controlling the growth, processing, ordering, and heterogeneity of nanomaterials and in understanding phenomena beyond the scale of single nanostructures – that must be overcome to exploit nanomaterials in technology.

In this seminar, I will present on 3 recent advances from my laboratory: (1) We have pioneered a scalable approach for assembling parallel arrays of ultrahigh purity semiconducting nanotubes. This approach has allowed us to create carbon nanotube field effect transistors (FETs) with current density that exceeds Si and GaAs, for the first time, which has been a goal of the nanoelectronics field for 20+ years. (2) We have discovered how to drive graphene crystal growth on Ge(001) surfaces with a giant anisotropy. This giant anisotropy is remarkable because it enables the rational synthesis of narrow, long, smooth, and oriented nanoribbons of graphene that are semiconducting whereas unconfined graphene is typically a semimetal. This result opens up the possibility of realizing hybrid carbon nanoelectronics directly on conventional group IV or III-V semiconductor wafer substrates. (3) Laminates of graphene oxide nanosheets have been shown to exhibit high water permeance and salt rejection. We have used experiments and modeling to show that the water transport pathways through such laminates are not as expected.
This work has implications in extending Moore’s Law, creating ultra-low energy logic circuits, developing higher bandwidth RF communication devices, and realizing next-generation water separation membranes.