Deterministic Fabrication of GaAs‐Quantum‐Dot Micropillar Single‐Photon Sources

Abstract This study investigates the performance of droplet‐etched GaAs quantum dots (QDs) integrated into micropillar structures using a deterministic fabrication technique. A unity QD positioning yield across 74 devices and consistent device performanceare demonstrated. Under p‐shell excitation, the QD decay dynamics within the micropillars exhibit biexponential behavior, accompanied by intensity fluctuations limiting the source efficiency to < 4.5%. Charge stabilization via low‐power above‐band LED excitation effectively reduces these fluctuations, doubling the source efficiency to 9%. Moreover, suppression of radiation modes is introduced by implementing cylindrical rings theoretically predicted to boost the collection efficiency by a factor of 4. Experimentally, only a modest improvement is obtained, underscoring the influence of even minor fabrication imperfections for this advanced design. These findings demonstrate the reliability of the deterministic fabrication approach in producing high‐yield, uniform devices, while offering detailed insights into the influence of charge noise and complex relaxation dynamics on the performance.