Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 49: Semiconductor Lasers II

HL 49.3: Talk

Thursday, March 21, 2024, 15:45–16:00, EW 561

High-beta quantum dot micropillar lasers operating at room temperature — •Sarthak Tripathi, Floriana Laudani, Kartik Gaur, Imad Limame, Ching-Wen Shih, Sven Rodt, and Stephan Reitzenstein — Inst. for Solid State Phys., Technical Univ. of Berlin, Germany

Room temperature micropillar lasing has attracted significant attention due to its potential applications in integrated photonics, optoelectronics, and neuromorphic computing. In this study, we present the fabrication and characterization of micropillar lasers showing a room-temperature emission wavelength around 960 nm. The epitaxially grown structure consists of a central one-lambda GaAs cavity with integrated InGaAs quantum dots (QDs), which is sandwiched between bottom and top distributed Bragg reflector (DBR) pair. Based on such planar microcavity structures high-Q micropillar cavities are fabricated using electron beam lithography and dry etching techniques, resulting in uniform pillar dimensions. Multiple layers of high-density InGaAs QDs are stacked in the active region in order to maximize the modal gain of the micropillar resonators for room-temperature operation. The density of dislocations and point defects in QDs heterostructures is strongly reduced by post-growth annealing which enables us to blue shift in wavelength without forfeiting their crystalline quality. Numerical simulations are carried out to optimize the fabrication parameters and subsequently validate the optical properties. Moreover, photoluminescence studies are conducted to evaluate the optical and laser properties of micropillar cavities.

Keywords: quantum dot; micropillar lasers; room temperature; metal organic chemical vapor deposition