Highly Sensitive Ammonia Gas Detection at Room Temperature by Integratable Silicon Nanowire Field-Effect Sensors

Enhancing sensitivity, selectivity, and intelligence of gas detection based on field-effect transistors: Principle, process, and materials

A sensor, serving as a transducer, produces a quantifiable output in response to a predetermined input stimulus, which may be of a chemical or physical nature. The field of gas detection has experienced a substantial surge in research activity, attributable to the diverse functionalities and enhanced accessibility of advanced active materials. In this work, recent advances in gas sensors, specifically those utilizing Field Effect Transistors (FETs), are summarized, including device configurations, response characteristics, sensor materials, and application domains. In pursuing high-performance artificial olfactory systems, the evolution of FET gas sensors necessitates their synchronization with material advancements. These materials should have large surface areas to enhance gas adsorption, efficient conversion of gas input to detectable signals, and strong mechanical qualities. The exploration of gas-sensitive materials has covered diverse categories, such as organic semiconductor polymers, conductive organic compounds and polymers, metal oxides, metal-organic frameworks, and low-dimensional materials. The application of gas sensing technology holds significant promise in domains such as industrial safety, environmental monitoring, and medical diagnostics. This comprehensive review thoroughly examines recent progress, identifies prevailing technical challenges, and outlines prospects for gas detection technology utilizing field effect transistors. The primary aim is to provide a valuable reference for driving the development of the next generation of gas-sensitive monitoring and detection systems characterized by improved sensitivity, selectivity, and intelligence.

Scalable Integration of High Sensitivity Strain Sensors Based on Silicon Nanowire Spring Array Directly Grown on Flexible Polyimide Films

The growth and integration of position-controlled, morphology-programmable silicon nanowires (SiNWs), directly upon low-cost polymer substrates instead of postgrowth transferring, is attractive for developing advanced flexible sensors and logics. In this work, a low temperature growth of SiNWs at only 200 °C has been demonstrated, for the first time, upon flexible polyimide (PI) films, via a planar solid-liquid-solid (IPSLS) growth mechanism. The SiNWs with diameter of ∼146 nm can be grown into precise locations on PI as orderly array and with preferred elastic geometry. Strain sensor array, built upon these spring-shape SiNWs integrated on PI, achieves a gauge factor (GF) of ∼90, sustains large stretching strains up to 3.3% (with 1.5 mm radius) and endures over 30,000 cycles. Strain sensors attached to the finger to monitor movements are also successfully demonstrated, showing high sensitivity and superior mechanical reliability, particularly suited for wearable health applications.

Silicon Nanowires via Metal-Assisted Chemical Etching for Energy Storage Applications

Silicon nanowires (SiNWs) have demonstrated great potential for energy storage due to their exceptional electrical conductivity, large surface area, and wide compositional range. Metal-assisted chemical etching (MACE) is a widely used top-down technique for fabricating silicon micro/nanostructures. SiNWs fabricated by MACE exhibit significant surface areas and diverse surface chemistry. Since the material composition and surface chemistry have a significant impact on the electrochemical energy storage performance, integrating SiNWs with diverse materials like porous carbon, metal oxides/sulfides, and polymers, can establish composites with excellent properties. Hence, it is imperative to meticulously fabricate SiNW-based materials with customizable morphologies and enhanced electrochemical energy-storage performance. This review provides an in-depth study of recent advancements in SiNW-based materials with enhanced performance for energy storage systems, such as supercapacitors (SCs) and lithium-ion batteries (LIBs). It includes a concise overview of the history, MACE synthesis, and characteristics of SiNWs. Further, it also explores the key elements that influence the MACE process of SiNWs and delves into structural engineering. Additionally, we introduce recent advances in SiNW-based materials for the design of high-performance energy-storage devices, namely SCs and LIBs. Finally, we present the crucial future prospects of SiNW-based materials for energy-storage applications.

Cyclometalated Iridium(III) Complex with Substituted Benzimidazole: pH Directed Organelle-Specific Localization Within Lysosome

We report the synthesis and pH dependent emission spectral behaviour of four emissive iridium(III) complexes (Ir1-Ir4) with two isomeric pairs of bis-trifluoromethyl appended benzimidazole ligands. The imidazolyl hydrogen(N-H) has been replaced by phenyl groups (N-Ph) in two ligands to understand the impact of hydrogen bonding on the photophysical properties of the complexes and it indeed plays interesting role in the charge-transfer dynamics. The pH dependent electronic spectral change is observed for two of the complexes. The enhancement of emission intensity is observed at different wavelength for pH<7 and pH>7 for Ir1 and Ir3. The emission sensing of biogenic amines with pka values ranging from 5.80-9.74 is reported along with cellular imaging. The complex Ir1 specifically localizes within lysosome (pH=4.5-5) and thus image this organelle with great precision. The detail electronic spectra and electrochemical behaviour were reported here along with TDDFT results.

Unveiling a growth temperature-dependent ultra-sensitive tetragonal scheelite BiVO4 thin film-based gas sensor for ammonia volatilization at room temperature

Ammonia (NH3) vapour is considered as a hazardous volatile, which has the potential to cause health concerns in humans. Exposure to NH3 can lead to potentially fatal, severe burn injuries to human eyes, can cause encephalopathy, and also affects various physiological systems, including the liver, the kidneys and the immune system. Due to these prime factors, the advancement of chemi-resistive ammonia gas sensors at room temperature has drawn considerable attention among researchers. In this current work, tetragonal scheelite (Ts)-BiVO4 thin films were deposited by varying the substrate (growth) temperature via the chemical spray pyrolysis method. The deposited thin films were subjected to structural, optical, morphological and gas sensing assessment. The gas sensing results indicate that the BV250 film has an ultra-high sensor response (I gas/I air = 900 for 75 ppm) towards ammonia vapour at room temperature. The pro-longevity of the sensor is outstanding (I gas/I air = 58.2 for 25 ppm) even after 50 days at room temperature. Furthermore, it demonstrates excellent selectivity, rapid response time (190 ± 4 s)/recovery time (16 ± 5 s) and repeatability (up to 4 cycles), and performs well in relatively humid conditions. This study offers insights into Ts-BiVO4 thin films as a sensing layer in a chemi-resistive gas sensor for ammonia detection at room temperature.

High-Performance Field-Effect Sensing of Ammonia Based on High-Density and Ultrathin Silicon Nanowire Channels

Ultrathin silicon nanowires (SiNWs), grown via a high-yield and low-cost catalytic approach, are ideal building blocks for the construction of highly sensitive field-effect transistor (FET) sensors. In this work, we demonstrate a high-density growth integration of an ultrathin SiNW array, with diameter down to DNW = 24 ± 3 nm and narrow NW-to-NW spacing of only 120 nm, fabricated via an in-plane solid-liquid-solid (IPSLS) approach. Junctionless bottom-gated SiNW FETs are successfully constructed, exhibiting a high on/off current ratio of >107 and a sharp subthreshold swing of 156 mV/dec These provide an excellent platform for realizing high-performance NH3 sensing at room temperature, with a high response of 96.9% at 25 ppm and 38.6% at 2.5 ppm, rapid response time of 7.9 s for 5% response (or 85.8 s for 50% response), and superior selectivity against common volatile organic compound gases in ambient environments. Finally, the field-effect sensing mechanism is attributed to the Schottky barrier modulation by the adsorbed NH3 molecules at the metal/SiNW interface, as confirmed through an epoxy-masked selective region comparative analysis. These results provide a solid basis for the ultrathin catalytic IPSLS-SiNWs to serve as advantageous one-dimensional (1D) channels for the scalable integration of various high-performance and flexible gas sensing applications.

BP/GaN and BP/GaP core/shell nanowires: theoretical insights into photovoltaic and gas-sensing abilities

DFT-based calculations were undertaken to, first, fully optimize and study the structural and electrical properties of bare BP nanowire (NW) in its hexagonal wurtzite (WZ) phase. The bare BP NW was found to have an indirect bandgap of 1.362 eV. Hence, the optimization of BP/GaN and BP/GaP core/shell nanowires (CSNWs) was performed to check if an indirect-to-direct band transition occurred. Both the CSNWs showed direct bandgaps of 0.225 eV and 1.252 eV, respectively. The Shockley-Queisser limits for the bare BP NW and BP/GaP CSNW were calculated and compared to gauge their respective photovoltaic efficiencies. The bare BP NW and BP/GaP CSNW yielded almost identical SQ efficiencies of 33.80% and 33.55%, respectively. However, as far as the nano- and micro-photovoltaic cell applications are concerned, the BP/GaP CSNW would be preferable, owing to its direct bandgap. Furthermore, the adsorption of some small oxide gases like carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2) and sulfur dioxide (SO2) gases on BP/GaN and BP/GaP CSNWs was studied. On the basis of the charge transfer and work function mechanisms, NO2 and SO2 gases showed selectivity to be detected by both the CSNWs. However, the very highly escalated desorption times for these gases would reduce the repeatability of sensors. Conversely, both BP/GaN and BP/GaP CSNWs could find applications in the fabrication of entrapment devices for NO2 and SO2. The current-voltage (I-V) curves for the CSNWs before and after adsorption were also plotted and analyzed. The occurrence of negative differential conductance (NDC) can be observed in both the CSNWs. The CO2, NO2 and SO2 gases show significantly higher values of current than the pristine BP/GaN CSNW for voltages beyond 0.5 V. Thus, these gases are good proponents to be detected by BP/GaN CSNWs with negligible selectivity amongst them. However, CO@BP/GaN is a stand-out case with a characteristically unique NDC region at 0.9 V. In the case of BP/GaP CSNWs, CO and CO2 gases can be selectively detected, with a unique NDC region for CO at 0.9 V. Thus, the BP/GaP CSNW, in particular, stands out as an extremely versatile material that can be used to fabricate nano-photovoltaic and nano-sensing devices of the next generation.

Room temperature gas sensors for NH3 detection based on the heterojunction of 2D Ti3C2Tx MXenes and Bi2S3

Bi2S3/Ti3C2Tx nanomaterials were successfully prepared through a simple hydrothermal method. Various methods were used for their characterization, including XRD, XPS, SEM, EDS, and BET, along with testing their gas-sensing properties. The results showed that the response value to 100 ppm ammonia at room temperature reached 107%, which was 14.1 times higher than that of pure few-layer MXene. After undergoing anti-humidity interference testing, we observed that Bi2S3/Ti3C2Tx exhibited a higher response value in real-time monitoring of ammonia as humidity increased. Specifically, under 90% humidity conditions, its response value reached 1.32 times that of normal humidity conditions. This exceptional moisture resistance ensures that the sensor can maintain stability, and even exhibit superior performance, in harsh environments. Therefore, it possesses excellent selectivity, high-moisture-resistance, and long-term stability, making it significant in the field of medical and health monitoring.

Advanced NH3 Detection by 1D Nanostructured La:ZnO Sensors with Novel Intrinsic p-n Shifting and Ultrahigh Baseline Stability

Due to its stability, transportability, and ability to be produced using renewable energy sources, NH3 has become an attractive option for hydrogen production and storage. Detecting NH3 is then essential, being a toxic and flammable gas that can pose dangers if not properly monitored. ZnO chemiresistive sensors have shown great potential in real NH3 monitoring applications; yet, research and development in this area are ongoing due to reported limitations, like baseline instabilities and sensitivity to environmental factors, including temperature, humidity, and interferent gases. Herein, we suggest an approach to obtain sensors with competitive performance based on ZnO semiconducting metal oxides. For this purpose, one-dimensional nanostructured pure and La-doped ZnO films were synthesized hydrothermally. Incorporating large rare earth ions, like La, into the bulk lattice of ZnO is challenging and can lead to surface defects that are influential in gas-sensing reactions. The sensors experienced a temperature-induced p-n shifting at about 100 °C, verified by the Hall effect and AC impedance measurements. The doped sensor showed exceptional stepwise baseline stability and outstanding performance at a relatively low operating temperature (150 °C) with a sensing response of 91 at best (@ 50 ppm NH3) and recorded a tolerance to water vapor up to 70% RH. Alongside p-n shifting, the enhanced performance was discussed in correlation with La doping-triggered changes in the nanostructural and surfacial properties of the films. We validated the proposed technique by producing similar sensors and performing multiple replicates to ensure consistency and reproducibility. We also introduced the fill factor concept into the gas sensor field as a new trustworthy parameter that could improve sensor performance assessment and help rate sensors based on deviation from ideality.

Microfluidic integrated gas sensors for smart analyte detection: a comprehensive review

The utilization of gas sensors has the potential to enhance worker safety, mitigate environmental issues, and enable early diagnosis of chronic diseases. However, traditional sensors designed for such applications are often bulky, expensive, difficult to operate, and require large sample volumes. By employing microfluidic technology to miniaturize gas sensors, we can address these challenges and usher in a new era of gas sensors suitable for point-of-care and point-of-use applications. In this review paper, we systematically categorize microfluidic gas sensors according to their applications in safety, biomedical, and environmental contexts. Furthermore, we delve into the integration of various types of gas sensors, such as optical, chemical, and physical sensors, within microfluidic platforms, highlighting the resultant enhancements in performance within these domains.

Ultracompact single-nanowire-morphed grippers driven by vectorial Lorentz forces for dexterous robotic manipulations

Ultracompact and soft pairwise grippers, capable of swift large-amplitude multi-dimensional maneuvering, are widely needed for high-precision manipulation, assembly and treatment of microscale objects. In this work, we demonstrate the simplest construction of such robotic structures, shaped via a single-nanowire-morphing and powered by geometry-tailored Lorentz vectorial forces. This has been accomplished via a designable folding growth of ultralong and ultrathin silicon NWs into single and nested omega-ring structures, which can then be suspended upon electrode frames and coated with silver metal layer to carry a passing current along geometry-tailored pathway. Within a magnetic field, the grippers can be driven by the Lorentz forces to demonstrate swift large-amplitude maneuvers of grasping, flapping and twisting of microscale objects, as well as high-frequency or even resonant vibrations to overcome sticky van de Waals forces in microscale for a reliable releasing of carried payloads. More sophisticated and functional teamwork of mutual alignment, precise passing and selective light-emitting-diode unit testing and installation were also successfully accomplished via pairwise gripper collaborations. This single-nanowire-morphing strategy provides an ideal platform to rapidly design, construct and prototype a wide range of advanced ultracompact nanorobotic, mechanical sensing and biological manipulation functionalities.

Microbial nanowires with genetically modified peptide ligands to sustainably fabricate electronic sensing devices

Nanowires have substantial potential as the sensor component in electronic sensing devices. However, surface functionalization of traditional nanowire and nanotube materials with short peptides that increase sensor selectivity and sensitivity requires complex chemistries with toxic reagents. In contrast, microorganisms can assemble pilin monomers into protein nanowires with intrinsic conductivity from renewable feedstocks, yielding an electronic material that is robust and stable in applications, but also biodegradable. Here we report that the sensitivity and selectivity of protein nanowire-based sensors can be modified with a simple plug and play genetic approach in which a short peptide sequence, designed to bind the analyte of interest, is incorporated into the pilin protein that is microbially assembled into nanowires. We employed a scalable Escherichia coli chassis to fabricate protein nanowires that displayed either a peptide previously demonstrated to effectively bind ammonia, or a peptide known to bind acetic acid. Sensors comprised of thin films of the nanowires amended with the ammonia-specific peptide had a ca. 100-fold greater response to ammonia than sensors made with unmodified protein nanowires. Protein nanowires with the peptide that binds acetic acid yielded a 4-fold higher response than nanowires without the peptide. The protein nanowire-based sensors had greater responses than previously reported sensors fabricated with other nanomaterials. The results demonstrate that protein nanowires with enhanced sensor response for analytes of interest can be fabricated with a flexible genetic strategy that sustainably eliminates the energy, environmental, and health concerns associated with other common nanomaterials.

1D and 2D Field Effect Transistors in Gas Sensing: A Comprehensive Review

Rapid progress in the synthesis and fundamental understanding of 1D and 2D materials have solicited the incorporation of these nanomaterials into sensor architectures, especially field effect transistors (FETs), for the monitoring of gas and vapor in environmental, food quality, and healthcare applications. Yet, several challenges have remained unaddressed toward the fabrication of 1D and 2D FET gas sensors for real-field applications, which are related to properties, synthesis, and integration of 1D and 2D materials into the transistor architecture. This review paper encompasses the whole assortment of 1D-i.e., metal oxide semiconductors (MOXs), silicon nanowires (SiNWs), carbon nanotubes (CNTs)-and 2D-i.e., graphene, transition metal dichalcogenides (TMD), phosphorene-materials used in FET gas sensors, critically dissecting how the material synthesis, surface functionalization, and transistor fabrication impact on electrical versus sensing properties of these devices. Eventually, pros and cons of 1D and 2D FETs for gas and vapor sensing applications are discussed, pointing out weakness and highlighting future directions.

Flexible Room-Temperature Ammonia Gas Sensors Based on PANI-MWCNTs/PDMS Film for Breathing Analysis and Food Safety

Gas sensors have played a critical role in healthcare, atmospheric environmental monitoring, military applications and so on. In particular, flexible sensing devices are of great interest, benefitting from flexibility and wearability. However, developing flexible gas sensors with a high sensitivity, great stability and workability is still challenging. In this work, multi-walled carbon nanotubes (MWCNTs) were grown on polydimethylsiloxane (PDMS) films, which were further modified with polyaniline (PANI) using a simple chemical oxidation synthesis. The superior flexibility of the PANI-MWCNTs/PDMS film enabled a stable initial resistance value, even under bending conditions. The flexible sensor showed excellent NH₃ sensing performances, including a high response (11.8 ± 0.2 for 40 ppm of NH₃) and a low limit of detection (10 ppb) at room temperature. Moreover, the effect of a humid environment on the NH₃ sensing performances was investigated. The results show that the response of the sensor is enhanced under high humidity conditions because water molecules can promote the adsorption of NH₃ on the PANI-MWCNTs/PDMS films. In addition, the PANI-MWCNTs/PDMS film sensor had the abilities of detecting NH₃ in the simulated breath of patients with kidney disease and the freshness of shrimp. These above results reveal the potential application of the PANI-MWCNTs/PDMS sensor for monitoring NH₃ in human breath and food.

Advances in silicon nanowire applications in energy generation, storage, sensing, and electronics: a review

Nanowire-based technological advancements thrive in various fields, including energy generation and storage, sensors, and electronics. Among the identified nanowires, silicon nanowires (SiNWs) attract much attention as they possess unique features, including high surface-to-volume ratio, high electron mobility, bio-compatibility, anti-reflection, and elasticity. They were tested in domains of energy generation (thermoelectric, photo-voltaic, photoelectrochemical), storage (lithium-ion battery (LIB) anodes, super capacitors), and sensing (bio-molecules, gas, light, etc). These nano-structures were found to improve the performance of the system in terms of efficiency, stability, sensitivity, selectivity, cost, rapidity, and reliability. This review article scans and summarizes the significant developments that occurred in the last decade concerning the application of SiNWs in the fields of thermoelectric, photovoltaic, and photoelectrochemical power generation, storage of energy using LIB anodes, biosensing, and disease diagnostics, gas and pH sensing, photodetection, physical sensing, and electronics. The functionalization of SiNWs with various nanomaterials and the formation of heterostructures for achieving improved characteristics are discussed. This article will be helpful to researchers in the field of nanotechnology about various possible applications and improvements that can be realized using SiNW.

Real-Time Monitoring of Breath Biomarkers with A Magnetoelastic Contactless Gas Sensor: A Proof of Concept

In the quest for effective gas sensors for breath analysis, magnetoelastic resonance-based gas sensors (MEGSs) are remarkable candidates. Thanks to their intrinsic contactless operation, they can be used as non-invasive and portable devices. However, traditional monitoring techniques are bound to slow detection, which hinders their application to fast bio-related reactions. Here we present a method for real-time monitoring of the resonance frequency, with a proof of concept for real-time monitoring of gaseous biomarkers based on resonance frequency. This method was validated with a MEGS based on a Metglass 2826 MB microribbon with a polyvinylpyrrolidone (PVP) nanofiber electrospun functionalization. The device provided a low-noise (RMS = 1.7 Hz), fast (<2 min), and highly reproducible response to humidity (Δf = 46−182 Hz for 17−95% RH), ammonia (Δf = 112 Hz for 40 ppm), and acetone (Δf = 44 Hz for 40 ppm). These analytes are highly important in biomedical applications, particularly ammonia and acetone, which are biomarkers related to diseases such as diabetes. Furthermore, the capability of distinguishing between breath and regular air was demonstrated with real breath measurements. The sensor also exhibited strong resistance to benzene, a common gaseous interferent in breath analysis.

Ultra-Confined Catalytic Growth Integration of Sub-10 nm 3D Stacked Silicon Nanowires Via a Self-Delimited Droplet Formation Strategy

Fabricating ultrathin silicon (Si) channels down to critical dimension (CD) <10 nm, a key capability to implementing cutting-edge microelectronics and quantum charge-qubits, has never been accomplished via an extremely low-cost catalytic growth. In this work, 3D stacked ultrathin Si nanowires (SiNWs) are demonstrated, with width and height of W_nw  = 9.9 ± 1.2 nm (down to 8 nm) and H_nw  = 18.8 ± 1.8 nm, that can be reliably grown into the ultrafine sidewall grooves, approaching to the CD of 10 nm technology node, thanks to a new self-delimited droplet control strategy. Interestingly, the cross-sections of the as-grown SiNW channels can also be easily tailored from fin-like to sheet-like geometries by tuning the groove profile, while a sharply folding guided growth indicates a unique capability to produce closely-packed multiple rows of stacked SiNWs, out of a single run growth, with the minimal use of catalyst metal. Prototype field effect transistors are also successfully fabricated, achieving I_on/off ratio and sub-threshold swing of >10⁶ and 125 mV dec^-1 , respectively. These results highlight the unexplored potential of versatile catalytic growth to compete with, or complement, the advanced top-down etching technology in the exploitation of monolithic 3D integration of logic-in-memory, neuromorphic and charge-qubit applications.

Rational Design of Field-Effect Sensors Using Partial Differential Equations, Bayesian Inversion, and Artificial Neural Networks

Silicon nanowire field-effect transistors are promising devices used to detect minute amounts of different biological species. We introduce the theoretical and computational aspects of forward and backward modeling of biosensitive sensors. Firstly, we introduce a forward system of partial differential equations to model the electrical behavior, and secondly, a backward Bayesian Markov-chain Monte-Carlo method is used to identify the unknown parameters such as the concentration of target molecules. Furthermore, we introduce a machine learning algorithm according to multilayer feed-forward neural networks. The trained model makes it possible to predict the sensor behavior based on the given parameters.

Highly Stretchable High-Performance Silicon Nanowire Field Effect Transistors Integrated on Elastomer Substrates

Quasi-1D silicon nanowires (SiNWs) field effect transistors (FETs) integrated upon large-area elastomers are advantageous candidates for developing various high-performance stretchable electronics and displays. In this work, it is demonstrated that an orderly array of slim SiNW channels, with a diameter of <80 nm, can be precisely grown into desired locations via an in-plane solid-liquid-solid (IPSLS) mechanism, and reliably batch-transferred onto large area polydimethylsiloxane (PDMS) elastomers. Within an optimized discrete FETs-on-islands architecture, the SiNW-FETs can sustain large stretching strains up to 50% and repetitive testing for more than 1000 cycles (under 20% strain), while achieving a high hole carrier mobility, Ion /Ioff current ratio and subthreshold swing (SS) of ≈70 cm2 V-1 s-1 , >105  and 134 - 277 mV decade-1 , respectively, working stably in an ambient environment over 270 days without any passivation protection. These results indicate a promising new routine to batch-manufacture and integrate high-performance, scalable and stretchable SiNW-FET electronics that can work stably in harsh and large-strain environments, which is a key capability for future practical flexible display and wearable electronic applications.

Designable Integration of Silicide Nanowire Springs as Ultra-Compact and Stretchable Electronic Interconnections

Stretchable electronics are finding widespread applications in bio-sensing, skin-mimetic electronics, and flexible displays, where high-density integration of elastic and durable interconnections is a key capability. Instead of forming a randomly crossed nanowire (NW) network, here, a large-scale and precise integration of highly conductive nickel silicide nanospring (SiNi_x -NS) arrays are demonstrated, which are fabricated out of an in-plane solid-liquid-solid guided growth of planar Si nanowires (SiNWs), and subsequent alloy-forming process that boosts the channel conductivity over 4 orders of magnitude (to 2 × 10⁴ S cm^-1 ). Thanks to the narrow diameter of the serpentine SiNi_x -NS channels, the elastic geometry engineering can be accomplished within a very short interconnection distance (down to ≈3 µm), which is crucial for integrating high-density displays or logic units in a rigid-island and elastic-interconnection configuration. Deployed over soft polydimethylsiloxane thin film substrate, the SiNi_x -NS array demonstrates an excellent stretchability that can sustain up to 50% stretching and for 10 000 cycles (at 15%). This approach paves the way to integrate high-density inorganic electronics and interconnections for high-performance health monitoring, displays, and on-skin electronic applications, based on the mature and rather reliable Si thin film technology.

Nanowire-based sensor electronics for chemical and biological applications

Detection and recognition of chemical and biological species via sensor electronics are important not only for various sensing applications but also for fundamental scientific understanding. In the past two decades, sensor devices using one-dimensional (1D) nanowires have emerged as promising and powerful platforms for electrical detection of chemical species and biologically relevant molecules due to their superior sensing performance, long-term stability, and ultra-low power consumption. This paper presents a comprehensive overview of the recent progress and achievements in 1D nanowire synthesis, working principles of nanowire-based sensors, and the applications of nanowire-based sensor electronics in chemical and biological analytes detection and recognition. In addition, some critical issues that hinder the practical applications of 1D nanowire-based sensor electronics, including device reproducibility and selectivity, stability, and power consumption, will be highlighted. Finally, challenges, perspectives, and opportunities for developing advanced and innovative nanowire-based sensor electronics in chemical and biological applications are featured.