Rachel S. Goldman

Professor

rsgold@umich.edu

2094 H.H. Dow Building

T: (734) 647-6821

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Synthesis of Low-Dimensional Semiconductor Structures: Fabrication of Nanopillar Arrays

Collaborators: J. F. Mansfield
Sponsor: MRSEC SEED
We are currently exploring the seeded-assembly of semiconductor nanopillars on substrates topographically patterned using FIB. We have already seeded ordered arrays of holes with controlled concentrations of Ga droplets using FIB implantation. These holes have nearly uniform sizes and shapes. By controlling the ion beam energy, current, and size, hole arrays with various sizes, depths, and periodicities may be produced. Interestingly, after scanning the ion beam over the patterned area, Ga dots form at the centers of the holes, resulting in the formation of ordered arrays of nearly uniform sized Ga dots. The Ga dot formation is likely due to the preferential agglomeration of the excess Ga in the holes. We are currently examining the mechanisms of Ga droplet formation and the interaction of various gases with the droplets. In addition, we are planning to use these ordered arrays of Ga dots as catalysts for vapor-liquid-solid growth of a variety of semiconductor nanopillars. We anticipate several novel applications of the nanopillars. For example, addressable UV or IR emitting ordered arrays of nanopillars may be used for nanopatterning photoresists for new generations of electronic circuitry. In addition, nanopillar arrays are a promising nano-platform for new logic technologies based upon quantum cellular automata. When combined with luminescent hybrid nanoparticles, electroluminescent nanopillar p-n junctions are promising for high-resolution full-color displays.
Highlights (Click an image for more information)
  • FIB-fabricated Ga Nanonots=> VLS Growth of GaN Nanopillars

    We are currently exploring the seeded-assembly of semiconductor nanopillars on substrates topographically patterned using FIB. We have already seeded ordered arrays of holes with controlled concentrations of Ga droplets using FIB implantation. These holes have nearly uniform sizes and shapes. By controlling the ion beam energy, current, and size, hole arrays with various sizes, depths, and periodicities may be produced. Interestingly, after scanning the ion beam over the patterned area, Ga dots form at the centers of the holes, resulting in the formation of ordered arrays of nearly uniform sized Ga dots. The Ga dot formation is likely due to the preferential agglomeration of the excess Ga in the holes. We are currently examining the mechanisms of Ga droplet formation and the interaction of various gases with the droplets. In addition, we are planning to use these ordered arrays of Ga dots as catalysts for vapor-liquid-solid growth of a variety of semiconductor nanopillars. We anticipate several novel applications of the nanopillars. For example, addressable UV or IR emitting ordered arrays of nanopillars may be used for nanopatterning photoresists for new generations of electronic circuitry. In addition, nanopillar arrays are a promising nano-platform for new logic technologies based upon quantum cellular automata. When combined with luminescent hybrid nanoparticles, electroluminescent nanopillar p-n junctions are promising for high-resolution full-color displays.