Deterministic fabrication of GaAs-quantum-dot micropillar single-photon sources

TL;DR

This paper presents a deterministic fabrication method for GaAs quantum-dot micropillar single-photon sources, achieving high device yield and exploring strategies to improve efficiency and collection through charge stabilization and mode suppression.

Contribution

The study introduces a reliable deterministic fabrication process for high-yield GaAs quantum-dot micropillar devices and analyzes their performance limitations and potential improvements.

Findings

Achieved unity QD positioning yield across 74 devices

Charge stabilization doubles source efficiency to ~9%

Suppression of radiation modes yields modest efficiency gains

Abstract

This study investigates the performance of droplet-etched GaAs quantum dots (QDs) integrated into micropillar structures using a deterministic fabrication technique. We demonstrate a unity QD positioning yield across 74 devices and consistent device performance. 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 $\sim$ 9%. Moreover, we introduce suppression of radiation modes by introducing 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. Our findings demonstrate the reliability of our 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.