On Ultrafast Photoconductivity Dynamics and Crystallinity of Black Silicon

Hendrik Pieter Porte, Dmitry Turchinovich, Saydulla Persheyev, Yongchang Fan, Mervyn J. Rose, Peter Uhd Jepsen

Research output: Contribution to journalJournal articleResearchpeer-review


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
JournalI E E E Transactions on Terahertz Science and Technology
Issue number3
Pages (from-to)331-341
Publication statusPublished - 2013


  • Black silicon
  • Carrier dynamics
  • Terahertz (THz) spectroscopy
  • Ultrafast conductivity

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