Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 44: Poster Session I
HL 44.4: Poster
Tuesday, March 15, 2011, 18:00–21:00, P3
Black silicon with femtosecond double laser pulses — •Anna Lena Baumann1, Thomas Gimpel2, Kay-Michael Günther2, Christian Lehmann3, Augustinas Ruibys1, Stefan Kontermann1, and Wolfgang Schade1,2 — 1Fraunhofer Heinrich-Hertz-Institute, Am Stollen 19, 38640 Goslar — 2Clausthal University of Technology, EFZN, EnergieCampus, Am Stollen 19, 38640 Goslar — 3FU Berlin, Fachbereich für Physik, Arnimallee 14, 14195 Berlin
We investigate the influence of double femtosecond laser pulses on topology, absorption, series and shunt resistance of p-doped silicon in 500 Torr SF6. A Michelson interferometer splits the laser pulses into pairs. The topology of p-doped silicon processed with laser pulse pairs at delay times from Δt = 16 fs to 30000 fs is different from single pulse black silicon, but similar for all delay times greater Δt = 0 fs. We process samples with 5 and 500 laser pulses per spot at delay times Δt = 50 fs and Δt = 100 fs. Optical characterization reveals the absorption characteristics in the visible and near-infrared range. We metalize the samples with an indium front and an aluminum back contact and measure series and shunt resistance. Overall absorption is greater for 500 pulse samples. In the visible range 5 pulse samples at Δt = 50 fs have slightly higher absorption. In the near-infrared both 5 and 500 pulse samples at Δt = 100 fs exhibit higher absorption values, with a difference greater 10% for the 5 pulse samples. All samples feature similar series and shunt resistance for the two delay times, while all 5 pulse samples display increased shunt resistance values.