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_1/3Nb_2/3)_0.7Ti_0.3]O₃ (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 ∼10³ A/W in the visible region, ∼10² A/W in the near-infrared (NIR) region, and ∼10¹ 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.