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Rapid and wide-range detection of NO <sub/>x</sub> gas by N-hyperdoped silicon with the assistance of a photovoltaic self-powered sensing mode
摘要： Wide dynamic range NOx sensors are vital for environment and health purposes, but few sensors could achieve wide range detection with ultralow and ultrahigh concentrations at the same time. In this article, the microstructured and nitrogen-hyperdoped silicon (N-Si) for NOx gas sensing is investigated systematically. Working by the change of surface conductivity, the sensor is ultra-sensitive to low concentration of NOx down to 11 ppb, and shows a rapid response/recovery time of 22/33 s for 80 ppb. When NOx concentration increases and exceeds a threshold value (10–50 ppm), an n–p conduction type transition is observed due to the inversion of the conduction type of major carriers, which limits the sensor’s dynamic range at high concentration. However, when the sensor works in a photovoltaic self-powered mode under the asymmetric light illumination (ALI), the limitation can be successfully overcome. Therefore, with the combination of the two working principles, a wide dynamic range stretching over six orders of magnitude (~0.011–4,000 ppm) can be achieved.
关键词： dynamic range,conduction type transition,asymmetric light illumination,hyperdoped silicon,self-powered gas sensing
更新于2025-09-19 17:13:59
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Controlled Growth and Thickness‐Dependent Conduction‐Type Transition of 2D Ferrimagnetic Cr <sub/>2</sub> S <sub/>3</sub> Semiconductors
摘要： 2D magnetic materials have attracted intense attention as ideal platforms for constructing multifunctional electronic and spintronic devices. However, most of the reported 2D magnetic materials are mainly achieved by the mechanical exfoliation route. The direct synthesis of such materials is still rarely reported, especially toward thickness-controlled synthesis down to the 2D limit. Herein, the thickness-tunable synthesis of nanothick rhombohedral Cr2S3 flakes (from ≈1.9 nm to tens of nanometers) on a chemically inert mica substrate via a facile chemical vapor deposition route is demonstrated. This is accomplished by an accurate control of the feeding rate of the Cr precursor and the growth temperature. Furthermore, it is revealed that the conduction behavior of the nanothick Cr2S3 is variable with increasing thickness (from 2.6 to 4.8 nm and >7 nm) from p-type to ambipolar and then to n-type. Hereby, this work can shed light on the scalable synthesis, transport, and magnetic properties explorations of 2D magnetic materials.
关键词： Cr2S3,chemical vapor deposition,controlled growth,conduction type transition
更新于2025-09-12 10:27:22