SKM 2023 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 33: Poster II

HL 33.47: Poster

Wednesday, March 29, 2023, 17:00–19:00, P1

Epitaxial growth of high-density short wavelength InGaAs QDs for low-threshold VCSELs — •Sarthak Tripathi, Kartik Gaur, Ching-Wen Shih, Imad Limame, Sven Rodt, and Stephan Reitzenstein — Inst. for Solid State Phys., Technical Univ. of Berlin, Germany

Self-assembled growth of InGaAs quantum dots by MOCVD is used to form the active region of low-threshold vertical-cavity surface-emitting lasers (VCSELs). In our work, we optimize the QD gain medium for room-temperature lasing at 935-955 nm which is attractive for gas sensing applications. Multiple layers of high-density InGaAs quantum dots are stacked in order to maximize the modal gain. The density of dislocations and point defects in QD heterostructures is strongly reduced by annealing which enables a significant reduction of the spacer thickness (thinner active region) between stacked QD layers without forfeiting their crystalline quality. Surface characterization is performed using atomic force microscopy AFM to determine the QD density. Moreover, during growth optimization photoluminescence studies are conducted to evaluate the optical properties of single and stacked layers of QD emitting in the target wavelength range. In future, the resulting QDs will be integrated in an active region embedded VCSELs with monolithically integrated high contrast grating (MHCG) hybrid structure.