Uncooled Mid-Infrared Sensing Enabled by Chip-Integrated Low-Temperature-Grown 2D PdTe₂ Dirac Semimetal

Abstract

Next-generation mid-infrared (MIR) imaging chips demand free-cooling capability and high-level integration. The rising two-dimensional (2D) semimetals with excellent infrared (IR) photoresponses are compliant with these requirements. However, challenges remain in scalable growth and substrate-dependence for on-chip integration. Here, we demonstrate the inch-level 2D palladium ditelluride (PdTe 2 ) Dirac semimetal using a low-temperature selfstitched epitaxy (SSE) approach. The low formation energy between two precursors facilitates low-temperature multiple-point nucleation (∼300 °C), growing up, and merging, resulting in self-stitching of PdTe 2 domains into a continuous film, which is highly compatible with back-end-of-line (BEOL) technology. The uncooled on-chip PdTe 2 /Si Schottky junction-based photodetector exhibits an ultrabroadband photoresponse of up to 10.6 μm with a large specific detectivity. Furthermore, the highly integrated device array demonstrates high-resolution room-temperature imaging capability, and the device can serve as an optical data receiver for IR optical communication. This study paves the way toward low-temperature growth of 2D semimetals for uncooled MIR sensing.

Recent advances in 2D transition metal dichalcogenide-based photodetectors: a review

“…1–5 Developed PD technologies have so far covered a wide range of applications, such as visible light detection for video imaging and digital cameras, ultraviolet (UV) irradiation for cell inspection and lithography, X-ray irradiation for biomedical imaging, wide-range infrared (IR) detection for night vision, environmental monitoring, optical communication, and quality testing spectroscopy, that have a significant impact on our daily lives. 6–16 PDs are categorized according to their several key figure of merits, such as high photogain, quantum efficiency, detectivity, and responsivity. To compare the direct photoresponse among different optical devices, responsivity (A W −1 ) and detectivity (Jones) are provided, which incorporates the variation in measurement conditions and detector geometries.…”

Reduced Graphene Oxide/Se Microtube p–p Heterojunction for Self-Powered UV–NIR Broadband Photodetectors

“…Broadband photodetectors (PDs) play a crucial role in various fields, including environmental monitoring, imaging, fire detection, astronomical observation, remote sensing, scientific research, as well as industrial applications. − Traditional photodetector detection systems have certain drawbacks, such as complex circuitry and high energy consumption. To better adapt to diverse working environments, self-powered PDs have emerged with the advantageous feature of low power consumption or even no external energy supply. − Electron–hole pair separation and operation can be accomplished with minimal external power by utilizing heterojunctions or Schottky junctions to create an internal electric field for self-powering. − Nevertheless, self-powered PD imposes stringent requirements on hybrid materials and entails a relatively intricate preparation process, leading to higher production costs and significantly limiting the widespread adoption and utilization of PDs in practical applications.…”

Investigations of MoS2-Based Self-Powered M–S–M Photodetectors with Low Defect Density and Fast Response and Low-Temperature Characteristics

“…Photodetector is an optoelectronic device that converts absorbed light energy into an electrical signal. It finds widespread applications in fields such as environmental monitoring, biomedicine, and imaging, , where high-speed response and high sensitivity are essential. The process of generating a photocurrent in a photodetector involves three main steps: First, light enters the absorption region of the device, causing electrons in the valence band to transition to the conduction band and generate electron–hole pairs.…”