Münster 1999 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 43: Optische Eigenschaften II
HL 43.7: Vortrag
Freitag, 26. März 1999, 11:00–11:15, H3
Enhancement of the emitted quantum well luminescence intensity due to surface plasmon excitation on a metallic grating — •N.E. Hecker1, T. Maier2, G. Strasser2, R. Höpfel1, and N. Sawaki3 — 1Institut f"ur Experimentalphysik, Universit"at Innsbruck, A-6020 Innsbruck — 2Institut f"ur Festk"orperphysik, Technische Universit"at Wien, A-1090 Wien — 3Department of Electrical Engineering and Electronics, Nagoya University, Nagoya, 464 Japan
We have dramatically increased (up to a factor of 6) the photoluminescence intensity emitted from a single GaAs/AlGaAs quantum well (QW) by preparing a thin metallic grating on the sample surface. The gold grating allows for efficient conversion of light into surface plasmons (SP) which, we show, are responsible for the enhanced luminescence emission. We have
photolithographically prepared the grating on half of the sample surface so that a direct comparison of the emitted luminescence intensity can be made with and without the grating. Simultaneous photoexcitation of the QW and SP’s is achieved by focussing a 754 nm laser diode onto the front surface of the sample. By selectively turning off the SP excitation via rotation of the sample or the excitation polarization, we can suppress the luminescence enhancement. We propose that a near field effect is responsible for the increase in the emitted luminescence intensity. Because the QW lies near the grating (50-70 nm from the surface), it acts as a probe for the local field enhancement due to the SP’s which effectively increases the excited carrier density.
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