Defect and interface engineering for high-performance 2D photodetectors

The performance of photodetectors based on two-dimensional (2D) materials is strongly influenced by defects and the interface [1]. The de-trap time of carriers from a deep trap could be prolonged by several orders of magnitude as compared to shallow trap, resulting in additional decay time of the device. We demonstrate that the trap states in 2D ReS₂ could be efficiently modulated by defect engineering through molecule decoration, and the both the response time and responsivity of the device is greatly improved [2]. We further elaborate that plasmon-induced hot electron transfer (HET) from tungsten suboxide nanocrystals to graphene is a sufficient fast process (<150 fs) to prevent carrier cooling and trapping processes. A fast near infrared (NIR) detector empowered by HET is demonstrated, and the response time is three-orders of magnitude faster than that based on common band-edge electron transfer [3]. Our results indicate that defect and interface engineering is a new strategy for implementation of efficient and high-speed photoelectric devices.

References:
[1] Hu ZH, Ni ZH*, et al. Chemical Society Reviews 47, 3100-3228 (2018)
[2] Jiang J, Ni ZH* et al. Advanced Materials 30, 1804332 (2018)
[3] Yu YF, Ni ZH* et al. Advanced Materials doi.org/ 10.1002/adma.201903829 (2019)