Uncooled Ultraviolet to Mid-infrared Multifunctional Photodetectors Based on Monolayer Graphene on Pb[(Mg_1/3Nb_2/3)_0.7Ti_0.3]O₃ Substrate

Graphene heralded a new era in optoelectronic research and prospective multifunctional devices. Here, we demonstrate uncooled ultraviolet to mid-infrared multifunctional photodetectors based on monolayer graphene on a Pb[(Mg 1/3 Nb 2/3 ) 0.7 Ti 0.3 ]O 3 (PMNPT) substrate, with capabilities in photodetection, memory, and signal processing. Using weak broad-spectral light, photoexcited holes in graphene are attracted by the stable spontaneous polarization within the PMNPT, inducing a gate tunable giant photogating effect. This enables multivalued saving and high-performance broad spectral photodetection (365 nm to 11.6 μm). Responsivities of ∼10 3 A/W in the visible region, ∼10 2 A/W in the near-infrared (NIR) region, and ∼10 1 A/W in the MIR region were achieved, respectively. Moreover, we developed neuromorphic hardware based on a proposed optoelectronic synaptic graphene transistor crossbar array and demonstrated exceptional signal processing accuracy of 93% in biological signal detection and image recognition. This neuromorphic hardware can also serve as a foundational functional unit, achieving high efficiency in data compression and feature extraction. Our approach marks a significant advancement toward graphene-based multifunctional devices.