Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 9: III-V semiconductors (other than nitrides)
HL 9.8: Vortrag
Montag, 12. März 2018, 17:00–17:15, EW 202
Infrared nanoscopy on Si-doped GaAs-InGaAs core-shell nanowires — •Denny Lang1,2, Leila Balaghi1,3, Emmanouil Dimakis1, René Hübner1, Susanne C. Kehr2, Lukas M. Eng2,3, Stephan Winnerl1, Harald Schneider1, and Manfred Helm1,2,3 — 1Helmholtz-Zentrum Dresden-Rossendorf, Germany — 2Technische Universität Dresden, Germany — 3cfaed - Center for Advancing Electronics Dresden, Germany
Semiconductor-based nanowires (NWs) are highly promising nm-sized building-blocks for future (opto-)electronic devices (i.e. photovoltaics, LEDs, THz detectors, polarizers, and lasers). Knowledge on the electrical characteristics of individual NWs is mandatory for any such application. Here, we investigate the plasma resonance of the free charge carriers in Si-doped GaAs-InGaAs core-shell NWs by applying scattering-type scanning near-field infrared microscopy (s-SNIM [1]) in the mid- to far-infrared wavelength range [2]. The shell doping may be varied over a broad range, revealing a plasma resonance around 10 µm for the highest doping level [3]. We compare IR-s-SNIM results obtained by both a CO2 laser and the pulsed free-electron laser light source, and observe a power-dependent red-shift of the plasma resonance, most probably arising through nonlinear effects such as intervalley scattering [4] occurring in strong electric fields.
[1] Stiegler, J. M. et al. Nano Lett. 10, 1387−1392 (2010).
[2] Kuschewski, F. et al., Appl. Phys. Lett. 108, 113102 (2016).
[3] Dimakis, E. et al., Nano Res. 5, 796−804 (2012).
[4] Razzari, L. et al., Phys. Rev. B 79, 193204 (2009).