Intelligent Dual-Mode Photodetector Based on Relaxor Ferroelectric PMN-PT Single Crystal

Conventional photodetectors are increasingly unable to achieve the demands of multifunctionality, low power consumption and miniaturization for the emerging intelligent imaging systems, because of their monotonous light-to-electric conversion mechanism. Ferroelectrics, known for their tunable polarization and extraordinary physical effects, offer promising solutions. Through mask-assisted deposition, relaxor ferroelectric Pb(Mg _1/3 Nb _2/3 ) O ₃ –PbTiO ₃ (PMN-PT) based photodetectors were constructed and exhibit dual-mode photoresponse characteristics. At 0 V, typical symmetric spikes caused by the pyroelectric effect (PE) can be seen from the visible to the near-infrared band. Intriguingly, upon 405 nm excitation at proper bias voltages, the photoresponse transforms into a bulk photovoltaic effect (BPVE) dominated square shape. The bias-modulated dual-mode photodetector owns promise potential in the advanced vehicle monitor system, in which the PE can be used to sense the approaching and subsequently active the BPVE to capture the vehicle, showing great advantage in energy saving. This work provides a feasible idea for intelligent optoelectronic devices by using the PE and BPVE of ferroelectrics.