On Ultrafast Photoconductivity Dynamics and Crystallinity of Black Silicon

H. P. Porte, D. Turchinovich, S. Persheyev, Y. Fan, M. J. Rose, P. U. Jepsen

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    9 Citations (Scopus)

    Abstract

    We investigate the carrier dynamics of thin films of black silicon, amorphous hydrogenated silicon which under laser annealing forms a microstructured surface with extremely high broadband optical absorption. We use Raman spectroscopy to determine the degree of crystallinity of the annealed surfaces, and investigate the dependence on crystallinity and fabrication method of the photoconductivity. Time-resolved THz spectroscopy is used to determine the evolution of the carrier scattering time and confinement of carriers on the picosecond time scale. We conclude that a fabrication method with high energy leading edge of the annealing laser results in black silicon with the largest photon-to-electron conversion efficiency, largest mobility, and longest carrier lifetime.

    Original languageEnglish
    Pages (from-to)331-341
    Number of pages11
    JournalIEEEI Transactions on Terahertz Science and Technology
    Volume3
    Issue number3
    DOIs
    Publication statusPublished - 2013

    Keywords

    • ultrafast conductivity
    • ON-SAPPHIRE
    • STRESS
    • CARRIER RELAXATION
    • SOLAR-CELLS
    • RESOLVED TERAHERTZ SPECTROSCOPY
    • VOLUME FRACTION
    • terahertz (THz) spectroscopy
    • Black silicon
    • EXCIMER
    • carrier dynamics
    • OPTICAL-PUMP
    • HYDROGENATED AMORPHOUS-SILICON
    • MICRO-RAMAN SPECTROSCOPY

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