BP/PdSe2 heterojunction device for broadband polarization-sensitive synaptic simulation, logic operation, navigation, all-day image processing and recognition.

Visual function is one of the most critical abilities of organisms to perceive the outside world, playing an indispensable role in the interaction between them. Especially, the polarization-sensitive visual function can process the polarized visual information in nature. However, this capability is a huge challenge for semiconductor devices. Here, an anisotropic BP/PdSe2 van der Waals (vdW) heterojunction device is proposed, which can realize wide-band photoelectric response from visible to short-wave infrared. The device shows a high responsivity of 0.459 A/W and an anisotropy ratio of 1.41 under 638 nm laser irradiation, which also exhibits good optical response to 405, 520, 980 and 1550 nm. Image edge processing and logical operations are realized by taking advantage of the polarization performance of the BP/PdSe2 device. In addition, the device also successfully achieves synaptic simulation. Interestingly, based on this, we have constructed artificial neural networks for image recognition. It realizes color recognition and shape recognition at day time, and still perform shape recognition at night for night vision, thus completing all-day image recognition. Besides, the device realizes polarization-sensitive synaptic simulation, mimicking the navigation behavior of bees by recognizing polarized light, and providing ideas for the research of artificial compound eyes. This work realizes multi-function application based on a single BP/PdSe2 vdW heterojunction device, which offers a potential technique for the development of intelligent optoelectronic systems.