Optimizing light extraction from non-planar site-controlled pyramidal quantum dot system: comparative modeling of three fabricable geometries

This work explores three different fabrication methods to improve light extraction efficiency of site-controlled pyramidal GaAs quantum dot (QD) system. In the theoretically analyzed structures (mimicking the as-obtained experimentally), we focus on the effects of geometry on light emission intensity, far-field profiles, and Purcell enhancement. The three methods include a back-etched approach, which exposes the pyramid’s apex, a pillar fabrication process, and a ‘mirrored’ pyramid technique. Simulation results suggest that all three techniques have the potential to improve light extraction from as grown structures, with the pillar method offering the highest extraction efficiency (43% for a numerical aperture of 0.999) and the back-etched configuration exhibiting a strong Purcell enhancement effect. The mirrored pyramid method is also of interest, as it provides a promising alternative to the back-etched approach, potentially simplifying the integration of electrical contacts for tuning QD properties. Ultimately, we emphasize the importance of precise control over the fabrication process to optimize the performance of this QD system for future applications in quantum information processing.