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Fast Near-Infrared Photodetection using III-V Colloidal Quantum Dots



Lee J. Richter, Bin Sun, Amin M. Najarian, Chao Zheng, Laxmi K. Sagar, Min-Jae Choi, Xiyan Li, Larissa Levina, Se-Woong Baek, Seungjin Lee, Ahmad R. Kirmani, Jehad Abed, Mengxia Liu, Peicheng Li, Oleksandr Voznyy, Zheng H. Lu, F. Pelayo G. de Arquer, Edward H. Sargent


Colloidal quantum dots (CQDs) are promising materials for IR light detection due to their tunable bandgap and their solution processing; however, to date, the time response of CQD IR photodiodes has been inferior to that provided by Si and InGaAs. We reasoned that the high permittivity of II-VI CQDs leads to slow charge extraction due to screening and capacitance; whereas III-Vs – if their surface chemistry could be mastered – offer a low permittivity and thus increased potential for high-speed operation. In initial studies, we found that the covalent character in InAs leads to imbalanced charge transport, the result of unpassivated surfaces and uncontrolled heavy doping. We report surface management using amphoteric ligand coordination and find that the approach addresses simultaneously the In and As surface dangling bonds. The new InAs CQD solids combine high mobility (0.04 cm2 V-1 s-1) with a 4x reduction in permittivity compared to PbS CQDs. The resulting photodiodes achieve a response time faster than 2 ns – the fastest photodiode among previously-reported CQD photodiodes – combined with an external quantum efficiency (EQE) of 30% at 940 nm.
Advanced Materials


photodiode, InA, quantum dot, near infrared


Richter, L. , Sun, B. , Najarian, A. , Zheng, C. , Sagar, L. , Choi, M. , Li, X. , Levina, L. , Baek, S. , Lee, S. , Kirmani, A. , Abed, J. , Liu, M. , Li, P. , Voznyy, O. , Lu, Z. , de Arquer, F. and Sargent, E. (2022), Fast Near-Infrared Photodetection using III-V Colloidal Quantum Dots, Advanced Materials, [online], (Accessed February 29, 2024)
Created June 29, 2022, Updated April 14, 2023