A resistivity-Type Palladium Decorated WSe2 Device for Ultralow Concentration Hydrogen Detection
Xin He, Jun‐Hui Yuan, Qian Li, Yingying Yang, Weijia Tang, Su Wu, Qiao Chen, Yang Xia, Zemin Zhang, Youwei Zhang, Shun Wang
Abstract
Due to the extremely small size of hydrogen atoms and the absence of molecular polarity, detecting Hydrogen gas (H 2 ) at the ppb level is typically challenging. Here, a resistivity-type H 2 sensor based on Pd nanoparticles decorated tungsten diselenide (WSe 2 ) device has been constructed. Benefiting from the inherently low background carrier concentration of WSe 2 , the device enables a significant reduction in the baseline current. By implementing responsivity optimization strategies, including morphological control of Pd nanoparticles, enhancement of carrier mobility, reduction of contact resistance, and optimization of the operating temperature, the sensor achieved a record-high responsivity of 628% (at 1000 ppm H 2 ) at approximately 65 °C, with a benchmark detection limit (LOD) of 10 ppb. This performance represents the highest level reported to date for H 2 sensors based on 2D materials. The device also exhibited excellent selectivity and stability. In addition, first-principles calculations reveal that the H 2 sensing mechanism is based on the modulation of carrier concentration in WSe 2 by Pd nanoparticles through the electron transfer process at the Pd/WSe 2 interface in H 2 environment. In a broader perspective, our work suggests strategies and methodologies for fabricating and optimizing high-performance H 2 sensors based on 2D materials and other semiconductor-based materials.