Ultrasensitive Near‐Infrared MoTe<sub>2</sub> Photodetectors with Monolithically Integrated Fresnel Zone Plate Metalens
Jie Qiao, Fu Feng, Guiyuan Cao, Shibiao Wei, Shuang Song, Tao Wang, Xiaocong Yuan, Michael G. Somekh
Abstract
Abstract Atomic layers of group‐VI 2D transition metal dichalcogenides (TMDCs) with substantial materials system and unique physicochemical properties have exhibited excellent performances in electronics and optoelectronics. However, photodetectors based on TMDCs suffer from poor sensitivity and optical absorption due to the weak phonon conversion efficiency and optical absorption due to their atomically thin feature. Here, taking advantages of miniaturization and integrability, all‐dielectric TiO 2 metalenses are designed based on the Fresnel diffraction effect and integrated with molybdenum ditelluride (MoTe 2 ) photodetectors. Owing to the enhancement of photon utilization efficiency, the corresponding integrated devices exhibit a high responsivity of 135.0 A W –1 , an excellent external quantum efficiency of 202.0%, and a specific detectivity of ≈4.05 × 10 12 Jones. These results indicate that the optoelectrical properties of 2D materials can be significantly optimized by integration with metalens and will accelerate the evolution of metalens in 2D optoelectronics fields.