General synthesis and properties of hetero-branched nanostructures
The bottom-up assembly of nanostructures from individual building blocks offers distinct advantages over traditional top-down fabrication techniques including greatly simplified and cost-effective fabrication and the enablement of unique properties only available at the nanoscale. There is a need for the development of nanostructures of increased compositional complexity to serve as building blocks for more advanced nanostructures and nanodevices.
For the first time branched nanowire structures combining more than one materials system have been demonstrated. As a result, the materials junctions are integral parts of the structure and are epitaxially integrated with each other. The technique is versatile, allowing a wide variety of materials combinations such as semiconductor/semiconductor, semiconductor/metal, semiconductor/oxide/semiconductor, and semiconductor/oxide/metal all within the same branched structure. This integration is distinct from the assembly of discrete nanowires and allows for unique combinations of materials currently unavailable such as p-n junctions and III-V semiconductors epitaxially integrated with silicon.
Nanowires are unique in that they can function as both actual devices and interconnects between devices, two of the key functions of an integrated nanosystem. Traditional nanowire integration schemes such as crossover junctions have involved the individual synthesis of nanowires of different compositions or doping. This synthesis technique allows for fine control over the structure, composition, doping and functionalities of each branch of the nanowire, enabling materials junctions to be integral to the nanostructure. Heterobranched nanowires have been demonstrated in basic electronic and photonic devices such as diodes, field effect transistors, and light-emitting didoes (LEDs). More complex nanosystems such as logic circuits, nanocomputers, and 3D biological sensors are possible.
Intellectual Property Status: Issued U.S. patent nos.: 8,058,640