Kim Byeongsu, Lee Sang Yeon, Ko Hyunseok, Lee Jihyung, Song Hyejeong, Cho Sungjun, Kim Yun Hoo, Lee Min-Ho, Lee Jung-Yong
School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
Information and Electronics Research Institute, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
Nat Nanotechnol. 2025 Feb;20(2):237-245. doi: 10.1038/s41565-024-01831-x. Epub 2024 Dec 18.
Colloidal quantum dots (CQDs) are promising for infrared photodetectors with high detectivity and low-cost production. Although CQDs enable photoinduced charge multiplication, thermal noise in low-bandgap materials limits their performance in IR detectors. Here we present a pioneering architecture of a CQD-based infrared photodetector that uses kinetically pumped avalanche multiplication. By applying a strong electric field to a thick CQD layer (>540 nm), electrons acquire kinetic energy beyond the bandgap of the CQD material, initiating kinetically pumped charge multiplication. Optimizing the dot-to-dot distance to approximately 4.1 nm improves performance by balancing impact ionization and electron hopping. Our optimized CQD-based infrared photodetector achieved a maximum multiplication gain of 85 and a peak detectivity of 1.4 × 10 Jones at 940 nm. This architecture offers potential for single-photon detection and ultrahigh detectivity applications.
胶体量子点（CQDs）有望用于具有高探测率和低成本生产的红外光电探测器。尽管CQDs能够实现光致电荷倍增，但低带隙材料中的热噪声限制了它们在红外探测器中的性能。在此，我们展示了一种基于CQD的红外光电探测器的开创性架构，该架构使用动力学泵浦雪崩倍增。通过对厚CQD层（>540nm）施加强电场，电子获得超过CQD材料带隙的动能，从而引发动力学泵浦电荷倍增。将点间距优化至约4.1nm可通过平衡碰撞电离和电子跳跃来提高性能。我们优化的基于CQD的红外光电探测器在940nm处实现了85的最大倍增增益和1.4×10琼斯的峰值探测率。这种架构为单光子探测和超高探测率应用提供了潜力。
