Van der Waals two-color infrared photodetector

TLDR

Infrared multispectral imaging demands inexpensive, miniaturizable detectors, yet widespread adoption is hindered by the high cost of epitaxial semiconductors and the need for complex cryogenic cooling. This work demonstrates a noncooled two‑color infrared photodetector capable of simultaneous temporal‑spatial blackbody detection in the near‑ and mid‑infrared. The device comprises vertically stacked back‑to‑back diode structures, and its two‑color signals are separated with ultralow crosstalk (~0.05%) by tailoring the built‑in electric field through an intermediate layer that serves as an electron‑collecting layer and hole‑blocking barrier. The detector achieves a room‑temperature specific detectivity of 6.4 × 10⁹ cm Hz¹ᐟ² W⁻¹ at 3.5 µm and enables promising NIR/MWIR imaging and absolute temperature sensing.

Abstract

With the increasing demand for multispectral information acquisition, infrared multispectral imaging technology that is inexpensive and can be miniaturized and integrated into other devices has received extensive attention. However, the widespread usage of such photodetectors is still limited by the high cost of epitaxial semiconductors and complex cryogenic cooling systems. Here, we demonstrate a noncooled two-color infrared photodetector that can provide temporal-spatial coexisting spectral blackbody detection at both near-infrared and mid-infrared wavelengths. This photodetector consists of vertically stacked back-to-back diode structures. The two-color signals can be effectively separated to achieve ultralow crosstalk of ~0.05% by controlling the built-in electric field depending on the intermediate layer, which acts as an electron-collecting layer and hole-blocking barrier. The impressive performance of the two-color photodetector is verified by the specific detectivity (D*) of 6.4 × 109 cm Hz1/2 W-1 at 3.5 μm and room temperature, as well as the promising NIR/MWIR two-color infrared imaging and absolute temperature detection.