Band-engineered GaTe/PdSe2 van der Waals heterostructures for broadband polarization-sensitive photodetectors with reverse rectification
image: A broadband and polarization-sensitive photodetector based on band-engineered GaTe/PdSe2 van der Waals heterojunction is demonstrated. The synergistic type-II band alignment and built-in fields enable reverse rectification, high responsivity (~103 A W⁻ ¹), and polarization ratios (> 4.60) from UV to NIR spectral regions, highlighting its potential for next-generation optoelectronic applications.
Credit: Nano Research, Tsinghua University Press
The relentless pursuit of photodetectors that combine broadband response, high sensitivity, and polarization discrimination is driven by demands in imaging, communication, and spectroscopic technologies. Two-dimensional van der Waals heterostructures, formed by stacking atomically thin layers, offer a revolutionary playground for band-structure engineering to create devices that surpass the inherent limitations of traditional semiconductors.
A research team led by Professors Mingqiang Liu from the Guizhou Normal University, Professors Jia-Qi Zhu, and Gui-Gen Wang from the Harbin Institute of Technology has developed a novel photodetector based on a GaTe/PdSe2 van der Waals heterostructure. This device overcomes fundamental material limitations to deliver unprecedented performance. The key to its success lies in its engineered type-II band alignment and a unique reverse rectification effect.
The fabricated device exhibits an ultra-low dark current of approximately 10⁻¹¹ A and a high reverse rectification ratio exceeding 10². It demonstrates excellent photoresponse across a wide band from 365 to 940 nm, covering ultraviolet, visible, and near-infrared wavelengths. The photoresponsivity reaches around 10³ A W⁻¹, with a specific detectivity of ~10¹³ Jones and an external quantum efficiency surpassing 10,000%. Furthermore, the device shows strong polarization sensitivity, with impressive polarization ratios of 5.39, 4.71, and 4.60 at wavelengths of 365 nm, 520 nm, and 940 nm, respectively.
“This heterostructure effectively breaks the intrinsic absorption limits of its constituent materials, GaTe and PdSe2,” said Professor Mingqiang Liu, a correspondence author of the study. “The synergistic interplay between the built-in electric field at the interface and the modulated Schottky barrier is crucial for achieving these superior performance metrics, including the unusual reverse rectification.”
Rigorous optoelectronic characterization, including power-dependent, polarization-dependent, and dynamic response measurements, confirmed the device's stable and fast response across the broad spectrum. This combination of broadband operation, high sensitivity, and polarization discrimination positions this technology as a powerful foundation for future high-performance photodetection systems, particularly in secure optical communications and multi-spectral imaging.
“Our work provides a new material platform and a viable design strategy for developing advanced photodetectors that are both broadband and polarization-sensitive,” added Professor Gui-Gen Wang. “We are now focusing on further improving the uniformity and integration potential of these devices for practical system-level applications.”
The article detailing this research, “Band-engineered GaTe/PdSe2 van der Waals heterostructures for broadband polarization-sensitive photodetectors with reverse rectification,” was published as a Just Accepted manuscript in Nano Research on December 1, 2025.
Other contributors include Jinshun Bi, Wenjun Xiao, and Abuduwayiti Aierken from the School of Physics and Electronic Science and the School of Integrated Circuit at Guizhou Normal University China.
This work was supported by the National Natural Science Foundation of China (Grant No. 62404060 and 12464021), Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic Systems (2023B1212010003), and Guizhou Provincial Science and Technology Foundation (ZK [2024] Youth 353 and MS-zk [2025] 265).
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.