A quasi-2D perovskite antireflection coating to boost the performance of multilayered PdTe2/Ge heterostructure-based near-infrared photodetectors

Abstract

A hybrid heterostructure composed of two-dimensional (2D) material/narrow bandgap semiconductor represents a promising platform for designing highly efficient and cost-effective near-infrared (NIR) photodetectors. However, performance enhancement is usually restricted by reduced light usage due to relatively high refractive indexes and low absorption coefficients of the hybrid heterostructures. Herein, we demonstrate that a quasi-2D perovskite thin film can serve well as an antireflection coating to greatly boost the performance of a multilayered PdTe₂/Ge heterostructure-based NIR photodetector. Specifically, upon the perovskite coating with an optimized thickness, photoresponsivity and specific detectivity can be improved significantly from ∼526.4 mA W⁻¹ to ∼976.2 mA W⁻¹ and from ∼2.43 × 10¹¹ Jones to ∼4.78 × 10¹¹ Jones, respectively, under a 1550 nm optical communication wavelength with a light intensity of ∼70 μW cm⁻² at zero bias. Meanwhile, other important performance parameters including dark current and response speed can maintain almost identical. Moreover, owing to the improved moisture resistance of the upper quasi-2D perovskite layer, the photodetector exhibits excellent device stability and operational durability under atmospheric conditions. The results not only provide a convenient route for improving the performance of NIR optoelectronic devices but also broaden the application scope of perovskite materials.