Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 24: Photovoltaik I

HL 24.5: Vortrag

Dienstag, 9. März 2004, 18:45–19:00, H15

Topological Features and Luminescence of Cu(InGa)Se₂ Absorbers with Sub-Micron Lateral Resolution — •Levent Gütay, Richard Fuhrmann, and Gottfied Heinrich Bauer — Institute of Physics, Carl von Ossietzky University Oldenburg

In a confocal microscope with sub-micron resolution we have simultaneously recorded optical reflection and photoluminescence of Cu(InGa)Se₂ absorbers and layer structures [1]. The optical reflection provides not a direct information on structural topological properties such as grain boundaries but is composed of photons reflected from the illuminated surface and weightened by a step-like acceptance function of the microscope aperture. Furthermore the reflection signal vs. topology is not unambiguous since in a wavy topology with spatial wave vector k as analyzed e.g. by afm-scans, the optical reflection measures intensities and may show maximum signal for reflection from tops and from valleys as well; the according pattern consequently contains wave vectors with 2k. We have created artificial optical reflection patterns by converting numerically afm-topology into 2D reflection. We compare 2D Fourier transforms of experimental with those of calculated reflection patterns and correlate laterally resolved pl-yields with topological features in the k-space.

[1] K. Bothe, G.H. Bauer, T. Unold, Thin Solid Films 362, 453 (2001)