Abstract: A patrol helmet and method for livestock and poultry farms is described herein. The patrol helmet is wirelessly connected to an online farm management system on a cloud platform. The patrol helmet includes a helmet body, a controller, an augmented reality (AR) display component, an infrared (IR) camera, and a visible light camera. The AR display component is secured at the bottom edge of the helmet body. Both the IR camera and the visible light camera are disposed on the helmet body. The IR camera, the visible light camera, and the AR display component each is electrically connected to the controller. The IR camera and the visible light camera are configured to photograph livestock or poultry in an area in front of a wearer to obtain a temperature and an image of the livestock or the poultry.

Abstract: The present disclosure relates to an infrared photodetector based on a van der waals heterostructure and a preparation method thereof. The infrared photodetector comprises a fully depleted van der waals heterostructure. The fully depleted van der waals heterostructure comprises a first n-type two-dimensional semiconductor layer, a p-type two-dimensional semiconductor layer, and a second n-type two-dimensional semiconductor layer which are sequentially provided from bottom to top. A fully depleted built-in electric field is formed by means of a sandwich structure including the first n-type two-dimensional semiconductor layer, the p-type two-dimensional semiconductor layer and the second n-type two-dimensional semiconductor layer, which can improve the light absorption efficiency while reducing the dark current of a device, and the separation rate and collection efficiency of photo-induced carriers are accelerated.

Abstract: The present disclosure provides a momentum-matching and band-alignment van der Waals (vdW) infrared photodetector and a fabrication method thereof. The photodetector includes a substrate, a dielectric layer, a Bi2O2Se layer, a black phosphorus (BP) layer, a metal source and a metal drain. The fabrication method includes: transferring, in a wet manner, the Bi2O2Se layer grown on the mica substrate onto the substrate having the dielectric layer, transferring the mechanically exfoliated BP layer through a micro-region fixed-point transfer device onto the Bi2O2Se layer, and separately fabricating the metal source and the metal drain on the Bi2O2Se layer and the BP layer by processes such as electron beam exposure and electron beam evaporation, thereby forming the momentum-matching and band-alignment vdW infrared photodetector having a vertical structure.