Uncooled Ultraviolet to Mid-infrared Multifunctional Photodetectors Based on Monolayer Graphene on Pb[(Mg1/3Nb2/3)0.7Ti0.3]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[(Mg1/3Nb2/3)0.7Ti0.3]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.