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The core of optical quantum information science is to use photonic quibits to encode, communicate, manipulate, and measure information, while single-photon efficient emitters (SPED) are one of the key devices to detect photonic qubits. Today, many SPED materials platforms, device architectures, and device performance are being actively explored.1 However, the fundamental study of ultrafast photophysics in situ devices remains a challenge. Another major challenge is current SPED devices rely on traditional semiconductor device physics. To break current device limitations, quantum materials including nanocrystal semiconductors and 2D semiconductors, may lead to novel device physics due to their unique ultrafast photophysics phenomena such as phonon bottleneck effect, multiple exciton interaction, and phase transition ultrafast locking. However, these phenomena are not fully understood.
Therefore, in this talk we use a unique ultrafast photocurrent spectroscopy of sub-20 ps time resolution to study the in situ next generation SPED, which is on the platform of solution-processed PbS nanocrystals and 2D black phosphorus. We study the ultrafast photocurrent under various conditions such as temperature (80K to 450 K), laser flux, and electrical field dependence (up to 105 V/cm). We address the ultrafast photophysics dynamics including carrier photogeneration, recombination, transport, and trapping.2-4
References
1. R. H. Hadfield, “single-photon detectors for optical quantum information applications” Nat. Photonics, 3, 696 (2009)
2. J. Gao, et. al. “Carrier Transport Dynamics in High Speed BlackPhosphorus Photodetectors” ACS Photonics, 5, 1412 (2018)
3. J. Gao, et. al. “Solution-Processed, High-Speed, and High-Quantum-Efficiency Quantum Dot Infrared Photodetectors” ACS Photonics, 3, 1217 (2016)
4. J. Gao, et. al. “Solution-Processed single-photon efficient detectors” under preparation.
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