A. James Clark School of Engineering

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Author: search.filters.author.Kan, Hung-ChihSubject: search.filters.subject.nanostructures

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    Directed Kinetic Self-Assembly of Mounds on Patterned GaAs (001): Tunable Arrangement, Pattern Amplification and Self-Limiting Growth
    (MDPI, 2014-05-12) Lin, Chuan-Fu; Kan, Hung-Chih; Kanakaraju, Subramaniam; Richardson, Christopher; Phaneuf, Raymond
    We present results demonstrating directed self-assembly of nanometer-scale mounds during molecular beam epitaxial growth on patterned GaAs (001) surfaces. The mound arrangement is tunable via the growth temperature, with an inverse spacing or spatial frequency which can exceed that of the features of the template. We find that the range of film thickness over which particular mound arrangements persist is finite, due to an evolution of the shape of the mounds which causes their growth to self-limit. A difference in the film thickness at which mounds at different sites self-limit provides a means by which different arrangements can be produced.
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    Effect of Extended Extinction from Gold Nanopillar Arrays on the Absorbance Spectrum of a Bulk Heterojunction Organic Solar Cell
    (MDPI, 2015-02-18) Tsai, Shu-Ju; Ballarotto, Mihaela; Kan, Hung-Chih; Phaneuf, Raymond J.
    We report on the effects of enhanced absorption/scattering from arrays of Au nanopillars of varied size and spacing on the spectral response of a P3HT:PCBM bulk heterojunction solar cell. Nanopillar array-patterned devices do show increased optical extinction within a narrow range of wavelengths compared to control samples without such arrays. The measured external quantum efficiency and calculated absorbance, however, both show a decrease near the corresponding wavelengths. Numerical simulations indicate that for relatively narrow nanopillars, the increased optical extinction is dominated by absorption within the nanopillars, rather than scattering, and is likely dissipated by Joule heating.