Vertical Barrier\nHeterostructures for Reliable and\nHigh-Performance Self-Powered Infrared Detection

With their fascinating properties, emerging two-dimensional\n(2D)\nmaterials offer innovative ways to prepare high-performance infrared\n(IR) detectors. However, the current performance of 2D IR photodetectors\nis still below the requirements for practical application owing to\nthe severe interfacial recombination, sharply raised contact resistance,\nand deteriorated metal conductivity at nanoscale. Here, we introduce\na vertical barrier heterojunction with a structure of PtSe<sub>2</sub>/GaAs that combines the excellent optoelectronic properties of transition\nmetal sulfides with topological semi-metals, which allows for an adjustable\nbandgap and high carrier mobility. The heterojunction was fabricated\nusing the wet transfer method. The heterostructures show significant\nrectification behaviors and photovoltaic effects, which allow it to\noperate as a self-driven photodetector at zero bias. The photoresponse\nparameters at 850 nm with zero bias voltage are 67.2 mA W<sup>–1</sup>, 6.7 × 10<sup>12</sup> Jones, 9.8%, 3.8 × 10<sup>5</sup>, 164 μs, and 198 μs for the responsivity, specific detectivity,\nexternal quantum efficiency, <i>I</i><sub>light</sub>/<i>I</i><sub>dark</sub> ratio, rise time, and fall time, respectively.\nMoreover, the heterojunction is highly sensitive to a wide spectral\nband from ultraviolet to near-infrared (360–1550 nm). At the\nsame time, this heterostructure demonstrates significant potential\nfor applications in IR polarized light detection and room-temperature\nhigh-resolution IR imaging. The excellent properties of the heterojunction\nmake it well-suited for high-performance, self-powered IR detection.