Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 33: Optical Properties 2

HL 33.8: Vortrag

Donnerstag, 8. September 2022, 17:15–17:30, H32

ZnSe-Based Microdisk Resonators in Novel Supported Geometry — •Wilken Seemann¹, Christian Tessarek¹, Siqi Qiao², Nils von den Driesch², Alexander Pawlis², Gordon Callsen¹, and Jürgen Gutowski¹ — ¹Institute of Solid State Physics, University of Bremen, Germany — ²Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Germany

Microdisk resonators often suffer from thermal problems due to the limited contact of the underetched structure to the substrate. In order to circumvent this, ZnSe-based microdisks were fabricated in a supported geometry, i.e., in contact to the substrate over their whole bottom facet. This is achieved by growing a ZnSe:Cl quantum well (QW) encapsulated in ZnMgSe barriers on an AlAs underlayer. Oxidation of the underlayer to Al₂O₃ after disk fabrication increases the refractive index difference between the resonator and the substrate.

Scanning electron microscopy reveals a high structural quality of the fabricated microdisks. Micro-photoluminescence measurements show that the resulting resonators support high-Q resonances near the band edge emission of the ZnSe:Cl QW and a large number of whispering gallery modes on the defect emission band. The latter can be reproduced using a plane-wave model. Raman measurements of microdisks, as well as the as-grown ZnSe-based structure on the oxidized and non-oxidized AlAs underlayer, are used to analyze the mechanical properties of the disk and the influence of the oxidation process on the strain in the QW structure.