Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Poster 1

HL 25.86: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P2

Measurement and calculation of spectral emissivity of semiconductor quantum emitters in dielectric environments — •Danial Kohminaei, Sayed Shkeebullah Sadat, Timo Kruck, Hans-Georg Babin, Andreas D. Wieck, and Arne Ludwig — Ruhr-Universität Bochum; Lehrstuhl für angewandte Festkörperphysik, Deutschland

Quantum dots (QDs) emit light divergently. For improved outcoupling of this photon emission, QDs are grown above so-called distributed Bragg reflectors (DBRs), which have a maximum reflectivity at the wavelength of the light of the QDs. Reflection also occurs unwantedly at the interface of the semiconductor to the vacuum. Therefore, when performing photoluminescence (PL) measurements, the measured spectral intensity of the emitted radiation strongly depends on the (dielectric) structure of the sample. Here we show a method for calibrating PL measurements to obtain the unaltered spectrum of the optically active medium. First, the spectral reflectivity is determined by reflectometer measurements, and compared to a simulation based on the transfer matrix method for the true layer thickness. This is then used to calculate the wavelength dependent standing wave field, the outcoupling efficiency and the quantum yield. Furthermore, the influence of the absorption of the exciting laser light in the semiconductor, on the overall spectrum will be analyzed. To validate the method, the calibrated spectra are compared with cleaved-edge PL measurements, where the QDs are excited from the side and the light is also collected from the side.