Porte, Hendrik Pieter2; Turchinovich, Dmitry5; Persheyev, Saydulla8; Fan, Yongchang8; Rose, Mervyn J.8; Jepsen, Peter Uhd7
1 Nanophotonics, Department of Photonics Engineering, Technical University of Denmark2 Department of Photonics Engineering, Technical University of Denmark3 Nanophotonics Theory and Signal Processing, Department of Photonics Engineering, Technical University of Denmark4 Teraherts Technologies and Biophotonics, Department of Photonics Engineering, Technical University of Denmark5 Fibers & Nonlinear Optics, Department of Photonics Engineering, Technical University of Denmark6 University of Dundee7 Center for Nanostructured Graphene, Center, Technical University of Denmark8 University of Dundee
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.
I E E E Transactions on Terahertz Science and Technology, 2013, Vol 3, Issue 3, p. 331-341
Black silicon; Carrier dynamics; Terahertz (THz) spectroscopy; Ultrafast conductivity