Asymmetric-field-modulated photodetectors based on plasmon-enhanced 2D/3D vdW heterostructures.

Abstract

Self-powered photodetectors normally display compromised zero bias performance because incomplete depletion of the photoactive layer limits the built-in driving force required for carrier separation. Here, we report a plasmon-functionalized bilayer-graphene/MoS2/p-GaN vertical heterojunction that integrates interfacial electrostatic engineering and dual-plasmon-resonance enhancement within a single device, enabling spectrally selective photoresponse without compromising responsivity. Experiments with density-functional-theory calculations reveal that the inserted bilayer graphene modifies interfacial charge redistribution and the asymmetric electrostatic profile across the stack, promoting efficient carrier separation under zero bias. Concurrently, Al and Au nanoparticles provide wavelength selective near-field enhancement in the ultraviolet and visible regimes, yielding photocurrent gains of ∼1.4 and ∼1.5 times under 254 and 532 nm illumination, respectively, along with maximum specific detectivities of 6.1 × 109 Jones and 1.9 × 109 Jones. This work highlights a scalable strategy for synergistically integrating interfacial electrostatic modulation with multi-band plasmonic selectivity, paving the way for low-power, multifunctional self-powered optoelectronics.

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