UC Berkeley

As semiconductor electronics are miniaturized to nanometer dimensions, new materials and device concepts are needed to meet the increasing demand for performance and energy at scale. A paradigm shift towards electronic components built at the molecular level is necessary to keep pace with this demand while maintaining the precision requirements and miniaturization trend set by the semiconductor industry. Bottom-up synthesized graphene nanoribbons (GNRs) are ideal candidates for this new paradigm due to their widely tunable electronic properties enabled by atomically precise synthesis from molecular precursors. GNRs have the potential to improve existing semiconductor technology while paving the way towards transformational semiconductor electronics based on tunneling devices, quantum bits, and spin transport. With the outstanding potential of GNRs comes a number of integration challenges to these applications. Chapter 2 of this dissertation introduces challenges faced to GNR integration into CMOS transistors and sensors related to (i) aggregation, (ii) structural homogeneity, and (iii) reproducibility that all serve to degrade device performance and yield. Chapter 3 introduces a method to synthesize atomically-thin, covalently-bonded 2D films of GNRs that resolves (i) aggregation and (iii) reproducibility challenges, resulting in improved device yield and performance. Further, Chapter 4 outlines a novel transfer method that enables access to (ii) structurally homogenous, spatially isolated graphene nanostructures on virtually any substrate. Finally, with a handle on solving the major integration challenges to GNR electronics, the work in Chapter 5 demonstrates a method for accessing intrinsically metallic GNRs – the final component towards a transformational GNR-based tunneling device concept described in Chapter 1.