Gas sensing performance of In2O3 nanostructures: A mini review

Effective detection of toxic and hazardous gases is crucial for ensuring human safety, and high-performance metal oxide-based gas sensors play an important role in achieving this goal. In2O3 is a widely used n-type metal oxide in gas sensors, and various In2O3 nanostructures have been synthesized for detecting small gas molecules. In this review, we provide a brief summary of current research on In2O3-based gas sensors. We discuss methods for synthesizing In2O3 nanostructures with various morphologies, and mainly review the sensing behaviors of these structures in order to better understand their potential in gas sensors. Additionally, the sensing mechanism of In2O3 nanostructures is discussed. Our review further indicates that In2O3-based nanomaterials hold great promise for assembling high-performance gas sensors

High-performance III-V MOSFET with nano-stacked high-k gate dielectric and 3D fin-shaped structure

A three-dimensional (3D) fin-shaped field-effect transistor structure based on III-V metal-oxide-semiconductor field-effect transistor (MOSFET) fabrication has been demonstrated using a submicron GaAs fin as the high-mobility channel. The fin-shaped channel has a thickness-to-width ratio (T(Fin)/W(Fin)) equal to 1. The nano-stacked high-k Al(2)O(3) dielectric was adopted as a gate insulator in forming a metal-oxide-semiconductor structure to suppress gate leakage. The 3D III-V MOSFET exhibits outstanding gate controllability and shows a high I(on)/I(off) ratio > 10(5) and a low subthreshold swing of 80 mV/decade. Compared to a conventional Schottky gate metal–semiconductor field-effect transistor or planar III-V MOSFETs, the III-V MOSFET in this work exhibits a significant performance improvement and is promising for future development of high-performance n-channel devices based on III-V materials

Structure regulation of two-dimensional lamellar NH2-UIO-66@MXene membrane for efficient H2/CO2 separation

Two-dimensional membranes are considered the next generation separation membrane with great application potential due to their excellent separation performance, good mechanical strength and thermal stability compared with traditional membrane materials. In this work, the flexible NH2-UIO-66@MXene membrane was successfully prepared for gas separation by loading NH2-UIO-66 particles onto Ti3C2 nanosheets based on an in-situ growth strategy. A LiF-HCl mixed solution was used as the etchant to obtain the Ti3C2 nanosheets. The loading of NH2-UIO-66 particles can regulate the interlayer spacing of Ti3C2 nanosheets, improving the specific surface area of Ti3C2 and the adsorption capacity for specific gases. The -NH2 group in NH2-UIO-66 enabled preferential adsorption of CO2 over H2, and the CO2 molecules adsorbed in the channel can even block the molecules passing through, increasing the resistance of CO2 diffusion. As a result, the NH2-UIO-66@Ti3C2 hybrid membrane realizes the selective separation of H2/CO2 mixed gas, and the separation selectivity is as high as 155. The gas separation selectivity and permeation of the final prepared NH2-UIO-66@MXene were enhanced and exceeded the upper limit of Robeson upper bound (2017)

Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures

Recently, the hydrogen gas sensing properties of semiconductor oxide (SMO) nanostructures have been widely investigated. In this article, we provide a comprehensive review of the research progress in the last five years concerning hydrogen gas sensors based on SMO thin film and one-dimensional (1D) nanostructures. The hydrogen sensing mechanism of SMO nanostructures and some critical issues are discussed. Doping, noble metal-decoration, heterojunctions and size reduction have been investigated and proved to be effective methods for improving the sensing performance of SMO thin films and 1D nanostructures. The effect on the hydrogen response of SMO thin films and 1D nanostructures of grain boundary and crystal orientation, as well as the sensor architecture, including electrode size and nanojunctions have also been studied. Finally, we also discuss some challenges for the future applications of SMO nanostructured hydrogen sensors

Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures

Recently, the hydrogen gas sensing properties of semiconductor oxide (SMO) nanostructures have been widely investigated. In this article, we provide a comprehensive review of the research progress in the last five years concerning hydrogen gas sensors based on SMO thin film and one-dimensional (1D) nanostructures. The hydrogen sensing mechanism of SMO nanostructures and some critical issues are discussed. Doping, noble metal-decoration, heterojunctions and size reduction have been investigated and proved to be effective methods for improving the sensing performance of SMO thin films and 1D nanostructures. The effect on the hydrogen response of SMO thin films and 1D nanostructures of grain boundary and crystal orientation, as well as the sensor architecture, including electrode size and nanojunctions have also been studied. Finally, we also discuss some challenges for the future applications of SMO nanostructured hydrogen sensors

Voltage-induced penetration effect in liquid metals at room temperature

© 2020 The Author(s) 2019. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd. Room-temperature liquid metal is discovered to be capable of penetrating through macro- and microporous materials by applying a voltage. The liquid metal penetration effects are demonstrated in various porous materials such as tissue paper, thick and fine sponges, fabrics, and meshes. The underlying mechanism is that the high surface tension of liquid metal can be significantly reduced to near-zero due to the voltage-induced oxidation of the liquid metal surface in a solution. It is the extremely low surface tension and gravity that cause the liquid metal to superwet the solid surface, leading to the penetration phenomena. These findings offer new opportunities for novel microfluidic applications and could promote further discovery of more exotic fluid states of liquid metals

Ultraviolet Detectors Based on Wide Bandgap Semiconductor Nanowire: A Review

Ultraviolet (UV) detectors have attracted considerable attention in the past decade due to their extensive applications in the civil and military fields. Wide bandgap semiconductor-based UV detectors can detect UV light effectively, and nanowire structures can greatly improve the sensitivity of sensors with many quantum effects. This review summarizes recent developments in the classification and principles of UV detectors, i.e., photoconductive type, Schottky barrier type, metal-semiconductor-metal (MSM) type, p-n junction type and p-i-n junction type. The current state of the art in wide bandgap semiconductor materials suitable for producing nanowires for use in UV detectors, i.e., metallic oxide, III-nitride and SiC, during the last five years is also summarized. Finally, novel types of UV detectors such as hybrid nanostructure detectors, self-powered detectors and flexible detectors are introduced