Interfacial Engineering of In<sub>2</sub>Se<sub>3</sub>/h-BN/CsPb(Br/I)<sub>3</sub> Heterostructure Photodetector and Its Application in Automatic Obstacle Avoidance System.

Niu, Yingying; Zhou, Xin; Gao, Wei; Fu, Maixia; Duan, Yule; Yao, Jiandong; Wang, Bing; Yang, Mengmeng et al. · ACS Nano · 2023

basic_science · Level V

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Abstract

Driven by the rapid development of autonomous vehicles, ultrasensitive photodetectors with high signal-to-noise ratio and ultraweak light detection capability are urgently needed. Due to its intriguing attributes, the emerging van der Waals material, indium selenide (In<sub>2</sub>Se<sub>3</sub>), has attracted extensive attention as an ultrasensitive photoactive material. However, the lack of an effective photoconductive gain mechanism in individual In<sub>2</sub>Se<sub>3</sub> inhibits its further application. Herein, we propose a heterostructure photodetector consisting of an In<sub>2</sub>Se<sub>3</sub> photoactive channel, a hexagonal boron nitride (h-BN) passivation layer, and a CsPb(Br/I)<sub>3</sub> quantum dot gain layer. This device manifests a signal-to-noise ratio of 2 × 10<sup>6</sup> with responsivity of 2994 A/W and detectivity of 4.3 × 10<sup>14</sup> Jones. Especially, it enables the detection of weak light as low as 0.03 μW/cm<sup>2</sup>. These performance characteristics are ascribed to the interfacial engineering. In<sub>2</sub>Se<sub>3</sub> and CsPb(Br/I)<sub>3</sub> with type-II band alignment promote the separation of photocarriers, while h-BN passivates the impurities on CsPb(Br/I)<sub>3</sub> and promises a high-quality carrier transport interface. Furthermore, this device is successfully integrated into an automatic obstacle avoidance system, demonstrating promising application prospects in autonomous vehicles.