Near-infrared polarized photodetectors hold significant importance for applications in remote sensing, imaging, and optical communications. Van der Waals heterostructures built from two-dimensional transition metal dichalcogenides represent a vital platform for developing next-generation optoelectronic devices. This study focuses on a novel device architecture: a homologous polymorphic heterojunction constructed from two distinct crystalline phases of molybdenum ditelluride (MoTe2)—the semimetallic 1T' phase and the semiconducting 2H phase. The integration of these two phases from the same chemical compound forms a junction with a favorable intrinsic band alignment. This built-in electronic structure efficiently facilitates the separation and transport of photogenerated charge carriers, thereby markedly boosting the device's overall responsivity.
The fabricated photodetector exhibits outstanding performance across a broad optical spectrum, spanning from 532 nm (visible) to 2200 nm (short-wave infrared). Under illumination by a 1310 nm near-infrared laser, the device demonstrates a high responsivity of 3.06 A·W–1, a specific detectivity of 3.2 × 109 Jones, and an exceptional external quantum efficiency of 289%. These metrics highlight its superior sensitivity in converting light into electrical signal. Furthermore, the device shows commendable response speed, with a rise time of 10.56 ms and a decay time of 6.26 ms, making it suitable for applications requiring rapid signal processing.
A key achievement of this work is the device's inherent polarization-sensitive detection capability. This functionality originates from the anisotropic structure within the heterojunction. The photocurrent exhibits a strong modulation effect with variations in the polarization angle of incident light, thereby achieving a high polarization sensitivity of up to 20.1. This intrinsic characteristic enables the device to directly decipher the polarization state of light without the need for external filters, adding a crucial dimension to its detection capabilities. The practical application potential of this technology has been convincingly validated through successful imaging demonstrations spanning from the visible to the near-infrared spectrum.
In summary, this research presents a high-performance near-infrared polarized photodetector based on a 1T'-MoTe2/2H-MoTe2 homologous polymorphic van der Waals heterojunction. It underscores the significant advantages of utilizing different phases of the same material for designing advanced optoelectronic devices. The findings provide a valuable and generalizable design strategy for developing future integrated, multifunctional sensing, and imaging systems.
Research by Professor Lianqing Zhu's team from Beijing Information Science and Technology University, China, highlights a significant advancement in photodetector technology. Their novel near-infrared (NIR) polarization-sensitive device represents more than a lab performance breakthrough; it provides a fundamental building block for next-generation sensing systems. This work equips machines with a new "sense" that extends beyond human vision—detecting not only visible light but also invisible NIR radiation and, crucially, the polarization direction of light. This dramatically expands the informational depth machines can access about their environment. The study was made available online on February 08, 2026 and was published in Volume 9 Issue 3 of the journal Opto-Electronic Advances on March 24, 2026.
In an era reliant on sensors for everything from smartphones to autonomous vehicles, there is a growing demand for detectors that capture richer optical information. Applications in challenging conditions—such as autonomous driving in poor visibility, non-invasive medical imaging, or precise environmental monitoring—require devices that go beyond traditional visible-light detection. The team's proposed heterojunction detector, based on the two-dimensional material MoTe2 in different structural phases, offers a promising solution to these needs.
The core innovation lies in a novel material design strategy. The researchers moved away from combining different materials. Instead, they used two distinct structural forms (the 1T' and 2H phases) of the same chemical compound, MoTe2, stacking them with atomic precision. This creates an efficient built-in electric field at their interface. When NIR light strikes the device, this field acts as a rapid charge "sorter," efficiently separating light-generated charges to produce a strong electrical signal. This grants the device high sensitivity and fast response in the NIR band.
Moreover, the anisotropic atomic structure of the material inherently enables the device to discern light's polarization. This ability adds a powerful new information dimension. Future imaging systems using this technology could analyze not just an object's shape and brightness, but also deeper properties like surface texture, stress, or material composition. This has broad potential, from improving the accuracy of satellite remote sensing in distinguishing man-made objects from natural terrain to enabling new methods for early biological detection in medicine.
In summary, this research is important because it pioneers a fundamental materials science approach—constructing high-performance heterojunctions from different phases of a single material. It demonstrates a generalizable design strategy: tailoring advanced electronic and optical functions by precisely controlling material structure at the atomic scale. This paves a clear path toward developing next-generation, miniaturized photonic chips that integrate detection, imaging, and data communication into unified, low-power systems.
The research team operates under the support of the Key Laboratory of the Ministry of Education and the National 111 Base, collaborating closely with Tsinghua University and the Royal Melbourne Institute of Technology. Their work spans multiple cutting‑edge fields, including infrared detection technology and optoelectronic integrated devices, intelligent sensing technology and systems, photonic computing chips, optical fiber sensing and systems, as well as photoelectric and vision detection systems. The team comprises more than 30 distinguished researchers, among whom are national‑level talents recognized under the "Hundred‑Thousand‑Ten‑Thousand Talent Project," young and middle‑aged experts with outstanding national contributions, Beijing Scholars, National Model Teachers, and National Outstanding Science and Technology Workers. Additionally, the team supervises over 290 doctoral and master's students currently pursuing their degrees.
The team has been honored with several prestigious titles, such as the Ministry of Education's Changjiang Scholar and Innovation Team, the Beijing Strategic Science and Technology Team, and the Beijing Outstanding Graduate Supervision Team. It has produced a series of internationally advanced research outcomes, including the publication of more than 500 academic papers, the authorization of over 160 invention patents, and the publication of 4 monographs. The team's achievements have been recognized with numerous awards, including the National Science and Technology Progress Award (Second Class), the Ministry of Education's Technology Invention Award (First Class), and more than 10 other provincial and ministerial‑level prizes. The research results have been widely applied in high‑impact sectors such as aerospace, advanced manufacturing, and national defense and military fields.
