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Recent Advances in Black Phosphorus-Based Electronic Devices
摘要： The rediscovery of graphene in the recent past has propelled the rapid development of exfoliation and other thin layer processing techniques, leading to a renewed interest in black phosphorus (BP). Since 2014, BP has been extensively studied due to its superior electronic, photonic, and mechanical properties. In addition, the unique intrinsic anisotropic characteristics resulting from its puckered structure can be utilized for designing new functional devices. In retrospect, significant efforts have been directed toward the synthesis, basic understanding, and applications of BP in the fields of nanoelectronics, ultrafast optics, nanophotonics, and optoelectronics. Here, the recent development of BP-based devices, such as nanoribbon field-effect transistors, complementary logic circuits, memory devices, and the progress made in meeting the challenges associated with contact resistance, in-plane anisotropy, and advanced gate stack, are reviewed. Finally, the prospects of 2D materials in meeting the International Technology Roadmap for Semiconductor requirements for the year 2030 are discussed.
关键词： black phosphorus,memory,gas sensors,field-effect transistors,complementary logic circuits
更新于2025-09-23 15:21:21
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[Nanostructure Science and Technology] Nanowire Electronics || One-Dimensional Nanowire-Based Heterostructures for Gas Sensors
摘要： Gas sensors with the ability to detect gaseous species in a quantitative and qualitative manner play an important role in various aspects in our daily lives. They can function as a feasible means to monitor air quality, environmental pollution, chemical detection, control of chemical processes, food quality, and medical diagnosis and so forth. One-dimensional (1D) nanostructures at least one dimension in the range of 1–100 nm (nanowires, nanorods, nanoribbons or nanobelts, nano?bers) have long been considered as promising building blocks for gas sensors [1–7]. The fascinating features of nanowires for gas sensing include high surface-to-volume ratio, sensitive surface, high crystallinity, high carrier mobility, low power consumption and ease for device integration [2, 6, 8, 9]. In 2001 nanowires were initially employed to fabricate gas sensors as proof-of-concept [2, 3]. Afterwards nanowires are drawing fast growing interest in the ?eld of gas sensing with an outcome of over 1200 publications in past 15 years from the Web of Science using the keywords nanowire and gas sensor (Fig. 7.1). It is important to note that among these publications metal oxide nanowires hold a dominant position, while other nanowires including organic polymers, metals, and other semiconductors only register a small part (12.6%). It is not strange that n-type ZnO and SnO2 nanowires are the most extensively studied materials for gas sensing because the electron mobility in ZnO and SnO2 is very high (160 and 200 cm2 V(cid:1)1 s(cid:1)1, respectively) with respect to that of other metal oxides such as In2O3, WO3 and TiO2 (100, 10 and 0.4 cm2 V(cid:1)1 s(cid:1)1, respectively).
关键词： speed,heterostructures,sensitivity,nanowires,gas sensors,metal oxide,selectivity,stability
更新于2025-09-23 15:21:21
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Fabrication and H <sub/>2</sub> -Sensing Properties of SnO <sub/>2</sub> Nanosheet Gas Sensors
摘要： Vertically formed and well-defined SnO2 nanosheets are easy to fabricate, involving only a single process that is performed under moderate conditions. In this study, two different sizes of a SnO2 nanosheet were concurrently formed on a Pt interdigitated electrode chip, with interconnections between the two. As the SnO2 nanosheets were grown over time, the interconnections became stronger. The ability of the fabricated SnO2 nanosheets to sense H2 gas was evaluated in terms of the variation in their resistance. The resistance of a SnO2 nanosheet decreased with the introduction of H2 gas and returned to its initial level after the H2 gas was replaced with air. Also, the response?recovery behaviors were improved as a result of the growth of the SnO2 nanosheets owing to the presence of many reaction sites and strong interconnections, which may provide multipassages for the electron transfer channel, leading to the acceleration of the reaction between the H2 gas and SnO2 nanosheets.
关键词： H2 sensing,single process fabrication,SnO2 nanosheets,gas sensors,electron transfer channel
更新于2025-09-23 15:21:01
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Controlled Growth of Vertically Oriented Trilayer MoS <sub/>2</sub> Nanoflakes for Rooma??Temperature NO <sub/>2</sub> Gas Sensor Applications
摘要： In present work, we introduce the controlled synthesis of few layer vertically oriented MoS2 flakes for high performance NO2 gas sensor applications. The density and the thickness of MoS2 nanosheets are controlled by varying the heating rate of the chemical vapor deposition process. Our study confirms that the nanoflakes of about three layers were obtained under the heating rate of 5 oC by using powders of MoO3 and S as precursors without using any catalyst. This is very advantageous because no catalyst was used, there was no need of buffer layer at the bottom of the MoS2 thin film flacks, thus omitting the leakage current when measuring the electrical signal and enhancing the gas sensing performance. Gas sensing measurements demonstrated that the interconnected vertically oriented MoS2 nanoflakes have a good response value of 20.1% to 0.5 ppm NO2 at RT, and 1.73% at 150 oC. The sensor showed full recovery characteristic at a measured temperature of 150 oC with response and recovery time of about 15 s, and 100 s, respectively. The sensor also exhibited good selectivity with the ignorable response to SO2, H2, NH3, H2S and a low detection limit of 42 ppb.
关键词： Few-layer MoS2,Gas sensors,Chemical vapor deposition,Vertically oriented
更新于2025-09-23 15:19:57
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Phosphorene as H <sub/>2</sub> S and CH <sub/>4</sub> Gas Sensor
摘要： First-principle calculations within density functional theory are carried out to investigate the adsorption of various gas molecules, including hydrogen sulfide and methane on two-dimensional monolayer phosphorene in order to fully exploit the gas sensing capabilities. The adsorption properties of different molecules in the environment on monolayer phosphorene base material is discussed in terms of the Mulliken charge transfer, energy band gap, adsorption energy. The prominent adsorption sites of methane, hydrogen sulfide, water, and oxygen on monolayer phosphorene are investigated at an atomistic level. Based on the results the transport properties of monolayer phosphorene exposed to these gas molecules are investigated both in zigzag and armchair direction using non-equilibrium Green function tuned with density functional theory. The results show that using both directions simultaneously as gas sensing can be an effective technique to distinguish hydrogen sulfide and methane gas molecules from others and demonstrate great selectivity.
关键词： phosphorene,methane,Green function,density functional theory,transport properties,device,hydrogen sulfide,gas sensors
更新于2025-09-23 15:19:57
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Continuous and Ultrafast Preparation of In(OH) <sub/>3</sub> , InOOH, and In <sub/>2</sub> O <sub/>3</sub> Series in a Microreactor for Gas Sensors
摘要： In(OH)3 and InOOH were synthesized in a high-temperature continuous flow microreactor, which was much faster than the hydrothermal synthesis in the Teflon-lined autoclave. The phase transition interval of In(OH)3 and InOOH is measured and the effect of aging temperatures on equilibrium compositions was also theoretically calculated. A transformation from nanorods to nanocubes was observed when the aging temperatures increased. In(OH)3 and InOOH were also synthesized with Sn dopant, which was proved to be beneficial for the transformation from In(OH)3 to InOOH. The sensors based on cubic and hexagonal In2O3 particles showed a fast response (4~5 s) and recovery (12~15 s) speed to acetone vapor at the optimum operating temperature of 290 oC. The sensor based on hexagonal In2O3 showed a higher response than that based on cubic In2O3. This work provided a rapid, continuous and high-temperature synthesis method of an In(OH)3, InOOH and In2O3 series.
关键词： Indium hydroxide (In(OH)3),Tin dopant,Indium oxide(In2O3),Indium oxyhydroxide (InOOH),Gas sensors
更新于2025-09-19 17:15:36
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Review—System-on-Chip SMO Gas Sensor Integration in Advanced CMOS Technology
摘要： The growing demand for the integration of functionalities on a single device is peaking with the rise of IoT. We are near to having multiple sensors in portable and wearable technologies, made possible through integration of sensor fabrication with mature CMOS manufacturing. In this paper we address semiconductor metal oxide sensors, which have the potential to become a universal sensor since they can be used in many emerging applications. This review concentrates on the gas sensing capabilities of the sensor and summarizes achievements in modeling relevant materials and processes for these emerging devices. Recent advances in sensor fabrication and the modeling thereof are further discussed, followed by a description of the essential electro-thermal-mechanical analyses, employed to estimate the devices’ mechanical reliability. We further address advances made in understanding the sensing layer, which can be modeled similar to a transistor, where instead of a gate contact, the ionosorped gas ions create a surface potential, changing the film’s conduction. Due to the intricate nature of the porous sensing films and the reception-transduction mechanism, many added complexities must be addressed. The importance of a thorough understanding of the electro-thermal-mechanical problem and how it links to the operation of the sensing film is thereby highlighted.
关键词： SMO gas sensors,CMOS integration,sensing mechanism,modeling,microheater design
更新于2025-09-19 17:15:36
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Graphene materials as a superior platform for advanced sensing strategies against gaseous ammonia
摘要： Ammonia (NH3) is an uncolored, toxic, corrosive, and reactive gas with a characteristic pungent stench. To date, quantitative analysis of NH3 concentrations have been made using conventional techniques (e.g., ion chromatography). In light of the complications involved in such applications, efforts have been made to develop detection methods of NH3 that are more sensitive and selective. In this respect, graphene-based sensors have attracted widespread attention because of graphene's distinctive electrical characteristics (e.g., low electrical signal noise and great mobility) and large surface area. This review article was designed to evaluate the potential usage of graphene-based gas sensors for effective detection of NH3. We aim to understand the recent advances in this challenging area of research by critically analyzing various experiments and comprehending their practical implications. This review critically compares the performance of graphene-based NH3 sensors with those of other nanomaterials for a broader understanding of the field. Also, we summarize the future prospects for advancement of graphene technology for NH3 sensing.
关键词： graphene,ammonia sensing,nanomaterials,electrochemical sensing,gas sensors
更新于2025-09-19 17:15:36
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Hierarchical WO3/ZnWO4 1D fibrous heterostructures with tunable in-situ growth of WO3 nanoparticles on surface for efficient low concentration HCHO detection
摘要： Hierarchical WO3/ZnWO4 1D fibrous heterostructures with tunable in-situ growth of WO3 nanoparticles on surface have been fabricated by the original one-step electrospinning technology combined with subsequent calcination process. Phase composition and morphology can be transformed from bead-like WO3 fibers to hierarchical WO3/ZnWO4 1D composites with the introduction of ZIF-8 into the precursor solution, which was mainly attributed to the combination of nucleation competition and crystal planes matching mechanisms during heat treatment. Compared with pure WO3 and WO3/ZnWO4-10%, WO3/ZnWO4-5% displayed the highest specific surface area value evaluated to be 268.57, indicating the prominent enhanced absorption behavior for targeted organic species. It is found that WO3/ZnWO4-5% composites have a response about 44.5 for 5 ppm HCHO, which was almost 8 times higher than that of sensor based on pure WO3 nanofibers at the optimal operating temperature. Meanwhile, the fast response/recovery time (12/14 s) and excellent stability characteristics (recycling, long-term, and humidity stability) towards HCHO can be also observed for WO3/ZnWO4-5% samples. The enhanced gas-sensing mechanism based on WO3/ZnWO4 composites can be ascribed to the synergistic effect of effective heterojunctions, large specific surface area, multiple reaction sites, and unique surface/interface electron transmission. The design and construction of hierarchical WO3/ZnWO4 1D materials attest to the significant potential of their use as novel gas sensors for detecting low concentration HCHO.
关键词： electrospinning,gas sensors,in-situ growth,HCHO,WO3/ZnWO4 heterostructures
更新于2025-09-19 17:15:36
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Chemisorption and sensitivity at semiconductor sensors revisited
摘要： In this work we derived the adsorption isotherms for non-dissociative and dissociative chemisorption of oxygen on a semiconductor surface. We extended the Wolkenstein theory for dissociative chemisorption and re-examined the basis that led to currently accepted formalisms in the literature. In particular, we correctly incorporated dissociative chemisorption as a second-order reaction. We determined band bendings and adsorbate coverages for different gas pressure and doping for a typical metal-oxide used in gas sensing. Finally, consequences for the sensor conductivity and sensitivity are discussed.
关键词： Chemisorption,Conductivity,Adsorption isotherms,Semiconductor gas sensors
更新于2025-09-19 17:15:36