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The vital issue for semiconductor pressure sensors is how to improve the sensitivity of their piezoresistive behavior. In this work, aiming to substantially promote the sensitivity, ZnO/SiC nanowire heterojunctions with various ZnO piezoelectric shell thicknesses were constructed by adjusting the depositing times of atomic layer deposition (ALD). It was found that the thicknesses of coupled ZnO nanolayers played a profound effect on the response of the heterojunctions to the change of stresses, representing the tailored piezoresistive behaviors. Accordingly, the piezoresistive coefficient was optimized to ~ 9.47 × 10–11 Pa−1 with an enhanced ΔR/R0 value of ~ 0.88, once the ZnO nanolayer thickness is fixed at ~ 20 nm, superior to most of pressures sensors based on SiC nanomaterials. This work may provide a novel strategy for exploring advanced SiC-based pressure sensors by coupling with suitable thickness of the piezoelectric nanolayer to improve piezoresistive behaviors. The tailored piezoresistive performance of ZnO/SiC nanowire heterojunctions with a adjusted shell thicknesses of ZnO piezoelectric nanolayers was reported, which had an enhanced piezoresistive coefficient of 9.47 × 10–11 Pa−1 and a ΔR/R0 of 0.88.

Purpose This study aimed to describe the epidemiologic characteristics of fracture in the elderly during the COVID-19. Methods This was a retrospective multi-centre study, which included patients who sustained fractures between 20 January and 19 February 2020. The collected data included patients' demographics (age and gender), injury-related (injury type, fracture location, injury mechanism, places where fracture occurred), and treatment modality. SPSS 23.0 was used to describe the data and perform some analysis. Results A total of 436 patients with 453 fractures were included; there were 153 males and 283 females, with an average age of 76.2 years (standard deviation, SD, 7.7 years; 65 to 105). For either males or females, 70-74 years was the most commonly involved age group. A total of 317 (72.7%) patients had their fractures occurring at home. Among 453 fractures, there were 264 (58.3%) hip fractures, accounting for 58.3%. Fall from standing height was the most common cause of fracture, making a proportion of 89.4% (405/453). Most fractures (95.8%, 434/453) were treated surgically, and 4.2% (19/453) were treated by plaster fixation or traction. Open reduction and internal fixation (ORIF) was the most used surgical method, taking a proportion of 49.2% (223/453). Conclusion These findings highlighted the importance of primary prevention (home prevention) measures and could be used for references for individuals, health care providers, or health administrative department during the global pandemic of COVID-19.

Photoelectrochemical (PEC) splitting of water into H2 and O2 by direct use of sunlight is an ideal strategy for the production of clean and renewable energy, which fundamentally relies on the explo...

Silicon carbide (SiC) is recognized as one of the most important candidates of third generation semiconductors with totally superior physical/chemical properties and exciting applications in opto/electronic devices. In the present work, we report the exploration of high-performance blue-light photodetectors on both rigid and flexible substrates by using SiC nanoarrays, which are aligned by dielectrophoresis. The rise and decay times of the photodetector assembled on a rigid (i.e., SiO2/Si) substrate are ∼0.39 and 0.56 s, respectively, with an external quantum efficiency of 3394%, which suggested that the SiC nanoarray photodetector has high sensitivity, fast responsivity and excellent reproducibility to light irradiation with a wavelength of 445 nm. Meanwhile, 73% of the maximum photocurrent response can be maintained after 6 months. Furthermore, the as-constructed flexible photodetector based on the polyethylene terepthalate (PET) substrate was highly stable against repeated bending, demonstrating that the as-constructed SiC photodetector was robust with high flexibility and electrical stability.

Making field emitters with both low turn-on field (Eto) and high current emission stability is one of the keys to push forward their practical applications. In the present work, we report the exploration of high-performance field emitters with designed sharp corners around SiC nanowires for fundamentally enhanced electron emission sites. The sharp corners with tailored densities are rationally created based on a facile etching technique. Accordingly, the emission sites and nanowires are integrated into a single-crystalline configuration without interfaces, which could offer the emitters with a robust structure to avoid the structural damage induced by the generated Joule heat and electrostatic forces over long-term field emission (FE) operation. Consequently, the Eto of the as-fabricated SiC field emitter is low down to 0.52 V/μm, which is comparable to the state-of-the-art one ever reported. Moreover, they have high electron emission stability with a current fluctuation of just 2% over 10 h, representing their promising applications in FE-based electronic units.

The giant piezoresistance effect (PRE) of semiconductors as featured by a high gauge factor (GF) is recognized as the prerequisite for realizing optimal pressure sensors with desired high sensitivity. In this work, we report the discovery of giant PRE in SiC nanobelts with a record GF measured using an atomic force microscope. The transverse piezoresistance coefficient along the [111] direction reaches as high as -312.51 × 10-11 pa-1 with a corresponding GF up to -1875.1, which is twice more than the highest value ever reported on SiC nanomaterials. The first-principles calculations reveal that B doping turns the acceptor states in the bandgap into deeper impurity levels, which makes the major contribution to the observed giant piezoresistance behavior. Our result provides new insights on designing pressure sensors based on SiC nanomaterials.

We report, for the first time, the exploration of an efficient photoanode based on an N-doped 4H-SiC nanochannel array for photoelectrochemical (PEC) water splitting, which is fabricated through an anodic oxidation approach. The SiC photoanode yields a high photocurrent density of 2.41 mA cm−2 at 1.4 V vs. Ag/AgCl under 1.5G simulated sunlight. Meanwhile, the as-constructed photoanode presents a fast photoresponse and wide photoresponse wavelength range. The high orientation of SiC nanochannel arrays, the single-crystal nature of the whole SiC film and the incorporated N dopants are responsible for the enhanced PEC performance, with the benefits of substantially improving the light capability and extending the optical absorption edges, as well as promoting transport and separation of photoexcited charge carriers.

Low turn-on fields (Eto) and high current emission stabilities are recognized as two crucial factors for the potential applications of field emission (FE) cathodes. In this work, graphene/SiC (G/SiC) heterojunction nanowire arrays were fabricated through catalyst-assisted pyrolysis of polymeric precursors. Aiming to explore advanced field emitters, G/SiC nanoarrays are designed to grow with a desired architecture including sharp tips, rough surface, incorporated dopants, and well-aligned configurations, which could fundamentally increase the effective emission sites, tailor the band gap structure, fully utilize the local field enhancement effect, and limit the shielding effect. The G/SiC emitters established exceptional FE properties with low and stable Eto of 1.10–1.12 V μm−1 when subjected to various anode–cathode distances, as well as a small current emission fluctuation of ∼3.7% over 5 h and high field enhancement factor up to 6383, which were comparable to the state-of-the-art ones previously reported, representing their totally excellent FE performance.

The third-generation semiconductor silicon carbide (SiC) is identified as one of the vitally important candidate materials to serve as a functional unit that performs stably and reliably under harsh working conditions, with respect to its excellent piezoresistive effects and robust physical/chemical characteristics. In the current work, we put forward the fabrication of SiC nanowires with co-doped N and P elements, which were fabricated via the pyrolysis of a polymeric material. The as-grown nanowires have a typical diameter of ∼260 nm with a 10 surface. The measured transverse piezoresistance coefficient π[10] of the established SiC nanowires increased from 5.07 to −146.30 × 10−11 Pa−1 as the loading forces varied from 24.95 to 130.51 nN. Meanwhile, the corresponding gauge factor (GF) was calculated up to ca. −877.79, which is higher than the values for all SiC nanostructures ever reported. The mechanism concerning the giant negative piezoresistance behavior of SiC nanowire is proposed. The current exploration may pave a new avenue for the development of highly sensitive and robust pressure sensors that could survive under harsh working conditions.

Improving the sensitivity of the piezoresistive behavior of semiconductor nanostructures is critically important because it is one of the keys to explore advanced pressure sensors with desired sensitivity. Herein, we reported a strategy for improving the piezoresistive behavior of SiC nanowire by coupling with the piezoelectric effect of ZnO nanolayers, which were grown by an atomic layer deposition approach. As a result, the detected current of the as-constructed ZnO/SiC heterojunction nanowires is 6 times more than SiC nanowires, suggesting its substantially improved sensitivity. Moreover, the measured Δ

We developed and validated 56 gene-specific semi-thermal asymmetric reverse PCR (STARP) markers for 46 genes of important wheat quality, biotic and abiotic stress resistance, grain yield, and adaptation-related traits for marker-assisted selection in wheat breeding. Development of high-throughput, low-cost, gene-specific molecular markers is important for marker-assisted selection in wheat breeding. In this study, we developed 56 gene-specific semi-thermal asymmetric reverse PCR (STARP) markers for wheat quality, tolerance to biotic and abiotic stresses, grain yield, and adaptation-related traits. The STARP assays were validated by (1) comparison of the assays with corresponding diagnostic STS/CAPS markers on 40 diverse wheat cultivars and (2) characterization of allelic effects based on the phenotypic and genotypic data of three segregating populations and 305 diverse wheat accessions from China and 13 other countries. The STARP assays showed the advantages of high-throughput, accuracy, flexibility, simple assay design, low operational costs, and platform compatibility. The state-of-the-art assays of this study provide a robust and reliable molecular marker toolkit for wheat breeding programs.

The piezoresistive effect of SiC low-dimensional nanostructures, together with their exclusive benefits of superior mechanical characteristics and could be integrated into the flexible devices that can withdraw large strain, promise to make a wide range of sensing devices application possible in the severe working conditions. In this work, we reported the transverse piezoresistance behaviours of n -type 3 C -SiC nanobelts with selected ( 1 1 ¯ 0 ) top surface and N dopants. The single-crystalline SiC nanobelts were achieved by the means of direct pyrolysis of polymeric precursors without catalysts, which had an average N doping level of ~ 6.02 at% and a typical width-to-thickness ratio of ~ 8. It was disclosed that the transverse piezoresistance coefficient π [ 1 1 ¯ 0 ] reached the maximum 10.29 × 10 –11 Pa −1 at a fixed external stress of 67.03 nN. Correspondingly, the gauge factor (GF) was calculated to be of ~ 61.7, which is higher than all the reported n -type SiC, intrinsic SiC, as well as most of the p -type SiC counterparted. The findings shed light on the fact that present n -type SiC nanobelts have the potential of becoming an outstanding contestant for the development of robust pressure sensors having elevated sensitivities.

Constructing semiconductor heterojunction with optimal structure and composition is highly desired to maximize the solar light utilization for photoelectrochemical (PEC) water splitting. Here, we reported the fabrication of BiVO4@ZnO heterojunction with a novel nanostructure for PEC water splitting via foaming-assisted electrospinning and subsequent atomic layer deposition (ALD) techniques. In such BiVO4@ZnO heterojunction, the isolated BiVO4 nanoparticles were packaged within the ZnO microbelt matrix. During PEC water splitting, the BiVO4 acts as the primary light absorber for wider solar spectral harvesting, and the ZnO prompts the transfer of the photo-excited high-energy electrons, which would render them with prolonged lifetime and enhanced separation of the photogenerated charge carriers. In addition, the microbelts architecture with a hollow channel can also effectively improve the interfacial charge separation and transportation. Accordingly, the PEC performances of BiVO4@ZnO hybrid microbelts were significantly enhanced with a photocurrent density up to ∼0.46 mA cm−2 (at 1.23 V vs. reversible hydrogen electrode (RHE) under simulated sunlight illumination), which is 15.3 times to that of pure BiVO4 counterpart (∼0.03 mA cm−2). The photocurrent density of the BiVO4@ZnO electrode can be further increased to 1.07 mA cm−2 at 1.2 V vs. RHE by adding hole scavenger (NaSO3) in the electrolyte solution under AM 1.5 G irradiation.

Fabrication of SiC nanoarrays is highly recommended owing to the fact that it is the key to push forward them being applied in optoelectronic devices. Nevertheless, majority of the reported works involving the growth of SiC low-dimensional nanostructures were often carried out under the harsh conditions (e.g., high temperatures and/or high pressures), which were teemed as the key obstacle for the accomplishment of their controllable and repeatable growth. In the current work, we reported the controllable and repeatable large-scale fabrication (up to centimeter×centimeter of width × length in area) of well-aligned, free-standing and transparent 4H-SiC nanohole arrays via anodic oxidation of SiC wafers at room temperature and atmospheric pressure conditions. It was discovered that the cycle period of the pulsed voltage played a crucial role in the formation of highly uniform nanohole arrays. In the meantime, the diameters, wall thickness and depth of the nanoholes could be modulated through the customization of the cycle times. Additionally, a possible mechanism was proposed for the formation of nanohole arrays.

Currently, one-dimensional all-inorganic CsPbX3 (X = Br, Cl, and I) perovskites have attracted great attention, owning to their promising and exciting applications in optoelectronic devices. Herein, we reported the exploration of superior photodetectors (PDs) based on a single CsPbI3 nanorod. The as-constructed PDs had a totally excellent performance with a responsivity of 2.92 × 103 A·W–1 and an ultrafast response time of 0.05 ms, respectively, which were both comparable to the best ones ever reported for all-inorganic perovskite PDs. Furthermore, the detectivity of the PDs approached up to 5.17 × 1013 Jones, which was more than 5 times the best one ever reported. More importantly, the as-constructed PDs showed a high stability when maintained under ambient conditions.

In the current work, we reported the engineering of homo/hetero junctions for boosting the photoelectrochemical (PEC) behaviors of all-inorganic perovskite SrTiO3 (STO) nanofibers. The engineering of these junctions was accomplished via spin-coating and electrospinning, followed by atomic layer deposition (ALD). The introduced STO film leads to the formation of the STO/STO homojunction, which provided an extended contact area to enhance the electron–hole mobility across the interface. Meanwhile, ALD-deposited ZnO allowed for the construction of the STO/ZnO heterojunction, which could build up internal electric fields at the interface to hinder the recombination of electron–hole pairs, causing a totally enhanced photoelectrochemical (PEC) activity. As a proof of concept, at an applied bias of 1.23 V vs. RHE, the photocurrent density of STO nanofibers with engineered homo/hetero junctions was enhanced more than 600 times that of their pristine STO counterpart. At 0 V vs. Ag/AgCl, their photocurrent density was improved up to ∼61.3 μA cm−2 in comparison to 0.12 μA cm−2 of their pristine STO counterpart. Furthermore, their photocurrent stability was increased from 79.62% of their pristine STO counterpart to 98% at 0.1 V vs. Ag/AgCl.

Low turn-on fields together with boosted stabilities are recognized as two key factors for pushing forward the implementations of the field emitters in electronic units. In current work, we explored superior flexible field emitters based on single-crystalline 3C-SiC nanowires, which had numbers of sharp edges, as well as corners surrounding the wire body and B dopants. The as-constructed field emitters behaved exceptional field emission (FE) behaviors with ultralow turn-on fields (Eto) of 0.94–0.68 V/μm and current emission fluctuations of ±1.0–3.4%, when subjected to harsh working conditions under different bending cycles, various bending configurations, as well as elevated temperature environments. The sharp edges together with the edges were able to significantly increase the electron emission sites, and the incorporated B dopants could bring a more localized state close to the Fermi level, which rendered the SiC nanowire emitters with low Eto, large field enhancement factor as well as robust current e...

As the “heart” of vacuum electronic device, the low turn-on field (Eto) of field emitters plays a crucial role for their practical application. In current work, we reported the designed fabrication of TiO2 field emitters with boosted field emission (FE) behaviors, by growing sharp branches and decorating Au nanoparticles (Au NPs) around the surfaces of preformed TiO2 nanorod arrays. It was found that the obtained nanoarrays with designed architectures could make a balance between the increased emission sites and limited field screening effect. The field enhancement factor (β) of as-fabricated TiO2 emitters was ~2 times to that the bare emitters. Moreover, their turn-on field and current density could be of 1.61 V/μm and ~4.95 mA/cm2, respectively, both of which were state-of-the-art ones among the TiO2 field emitters ever reported.

Accurate segmentation of brain tumour means that surgeons accurately remove the tumour without damaging other healthy tissues. At present, due to the differences in human brains, the widely used manual brain tumour segmentation method cannot guarantee its accuracy and reliability. Therefore, it is of great social and practical significance to work out an automatic and accurate brain tumour segmentation method based on the computer-aided technology. This paper proposes a novel brain tumour segmentation method based on the deep learning model of stacked de-noising auto-coder. Firstly, by model training, it obtains the parameters of the deep learning network, and then it extracts high-level abstract features of the input image data through the network and uses these features to translate the segmentation of brain tumour to the classification of image blocks. Finally, this paper applies the proposed method for the MRI images of real brain tumour patients to carry out segmentation of brain tumours, and then compares it with the manual brain tumour segmentation method. The results show that the computer-aided brain tumour segmentation method is more effective and accurate and can provide reliable basis for the removal of brain tumours by surgeons without damaging normal tissues.

In the present work, we reported the current emission from P-doped SiC nanowire field emitters, which were synthesized via catalyst-assisted pyrolysis of polysilazane precursors. Directed by F–N theory for enhanced field emission (FE) behaviors, the emitters were grown into nanostructures with two desired characteristics, namely with an ultrahigh aspect ratio as well as incorporated P dopants, which brought profound enhancements to the field enhancement factor (β) and turn-on field (Eto). The as-grown SiC nanowires (SiCNWs) exhibit an aspect ratio over 1500 with a uniform spatial distribution of P dopants. The FE measurements exhibit that the SiCNWs possessed a field enhancement factor up to 11657 and an ultralow Eto of 0.47 V μm−1, which was little achieved among the reported studies. The current emission fluctuations are ∼±4.0% over 5 h, suggesting their good electron emission stability. We mainly attributed the totally excellent FE performances to the ultra-high aspect ratio and the incorporated P dopants of the obtained SiCNWs, which could synergistically cause a significant increase of the field enhancement factor and a decrease of the work function.

High-performance solar-blind UV (ultraviolet) photodetectors (PDs) based on low-dimension semiconducting nanostructures with high sensitivity, excellent cycle stability, and the ability to operate in harsh environments are critical for solar observations, space communication, UV astronomy, and missile tracking. In this study, TiO2-ZnTiO3 heterojunction nanowire-based PDs are successfully developed and used to detect solar-blind UV light. A photoconductive analysis indicates that the fabricated PDs are sensitive to UV illumination, with high sensitivity, good stability, and high reproducibility. Further analysis indicates that the rich existence of grain boundaries within the TiO2-ZnTiO3 nanowire can greatly decrease the dark current and recombination of the electron-hole pairs and thereby significantly increase the device’s photosensitivity, spectra responsivity (1.1 × 106), and external quantum efficiency (4.3 × 108 %). Moreover, the PDs exhibit good photodetective performance with fast photoresponse and recovery and excellent thermal stability at temperatures as high as 175 °C. According to these results, TiO2-ZnTiO3 heterojunction nanowires exhibit great potential for applications in high-performance optical electronics and PDs, particularly next-generation photodetectors with the ability to operate in harsh environments.

In this work, polycrystalline WO3 nanobelts were fabricated via an electrospinning process combined with subsequent air calcination. The resultant products were characterized by X-ray diffraction, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy in regard to the structures. It has been found that the applied voltage during the electrospinning process played the determined role in the formation of the WO3 nanobelts, allowing the controlled growth of the nanobelts. The ultraviolet (UV) photodetector assembled by an individual WO3 nanobelt exhibits a high sensitivity and a precise selectivity to the different wavelength lights, with a very low dark current and typical photo-dark current ratio up to 1000, which was the highest for any WO3 photodectectors ever reported. This work could not only push forward the facile preparation of WO3 nanobelts but also represent, for the first time, the possibility that the polycrystalline WO3 nanobelts could be a promising building block for the highly efficient UV photodetectors.

Current emission stability is one of the key issues for field emitters for them to be practically applied as electron sources. In the present work, large-scale and well-aligned B-doped SiC nanoneedle arrays have been grown on 6H-SiC wafer substrates via pyrolysis of polymeric precursors. The measured field emission (FE) characteristics suggest that the turn-on fields of the as-synthesized SiC nanoneedle arrays are reduced from 1.92 to 0.98 V μm(-1) with temperature increasing from room temperature (RT) to 500 °C, suggesting their excellent FE performances. The slightly changed current fluctuations (only ∼1.3%) between RT and 200 °C confirm that the present SiC nanoarrays with B dopants could be highly stable field emitters to be used in service under harsh conditions of high temperatures.

Recently, ultraviolet (UV) photodetectors based on TiO2 semiconductors have attracted intensive attention, due to their wide applications in environmental and biological research, optical communication, astronomical investigations and missile launch detection. However, there still remain material- and fabrication-related obstacles in realizing highly efficient UV photodetectors. Here, we reported the exploration of the efficient UV photodetectors based on the highly ordered TiO2 nanotube arrays (TNAs). The TNAs were prepared by a two-step anodic oxidation with tailored tube lengths and wall thicknesses, and then transplanted to a transparent FTO substrate to construct a front-illuminated photodetector. The as-assembled photodetectors exhibit a satisfactory stability and wavelength selectivity with a high photocurrent, photo-to-dark current ratio and responsivity up to 1395 μA, 10730 and 176.3 A W−1 under the UV illumination of 350 nm (45 μW cm−1) at a given bias of 2 V with TiO2 tube length of 14.7 μm, respectively, suggesting their promising applications in efficient UV photodetectors.

How to limit the recombination of photogenerated carriers is one of the grand challenges for exploring efficient photoelectrochemical (PEC) cells. In the present work, an engineering of oxygen vacancies within photoanodes by constructing distributed homojunctions for enhanced PEC performance is proposed. The distributed homojunctions are attributed to the formed hierarchical layers within the photoanodes, which were accomplished by one-step aqua-regia hydrothermal strategy. It is evidenced that the distributed homojunctions produced an improved spatial distribution of built-in electric field, thus significantly facilitating the charge separation for the PEC cells. As a proof of concept, the assembled WO3 photoanode exhibits a photocurrent density up to 1.81 mA cm−2 at 1.23 V vs. RHE in neutral electrolyte solution under AM 1.5G illumination without any cocatalysts and dopants, which is the state-of-the-art one ever reported.

Fabrication of well-aligned one-dimensional (1D) nanostrucutres is critically important and highly desired since it is the key step to realize the patterned arrays to be used as the display units. In the present work, we report the large-scale and well-aligned growth of n-type SiC nanowire arrays on the 6H-SiC wafer substrates via pyrolysis of polymeric precursors assisted by Au catalysts. The obtained n-type SiC nanowires are highly qualified with sharp tips and numerous sharp corners around the wire bodies, which bring the emitters excellent field emission (FE) performance with low turn-on fields (1.50 V/μm), low threshold fields (2.65 V/μm), and good current emission stabilities (fluctuation3.8%). The work abilities of the n-type SiC tower-like nanowire arrays under high-temperature harsh environments have been investigated, suggesting that the resultant field emitters could be well serviced up to 500 °C. The temperature-enhanced FE behaviors could be attributed to the reduction of the work function induced by the rise of temperatures and the incorporated N dopants. It is believed that the present well-aligned n-type SiC tower-like nanowire arrays could meet nearly all stringent requirements for an ideal FE emitter with excellent FE properties, making their applications very promising in displays and other electronic nanodevices.

The thermal stability of quantum dots (QDs) is considered as one of the key factors for their applications in various devices, due to the inevitable current induced Joule heat. In this work, we report the temperature-dependent photoluminescence (PL) of Mn:ZnCdS QDs, with a designed structure of MnS/ZnS/CdS, in the temperature range from 80 to 480 K. It is found that the highest PL quantum yield (QY) of the Mn:ZnCdS QDs can reach up to 65% even at the high temperature of 360 K. Moreover, the optical performance exhibits an excellent thermal stability, since the close-packed Mn:ZnCdS QDs and the QDs/organic blend films can maintain 90% of their initial intensity at 400 K for a long time. Furthermore, the thermal quenching mechanism of Mn2+ ion emission is proposed. The results of the present work suggest that QDs with high PL QYs and enhanced thermal stabilities could be realized by blocking the nonradiative recombination centers with thick CdS shells.

In this study, UV photodetectors (PDs) based on SiC nanowire films have been successfully prepared by a simple and low-cost drip-coating method followed by sintering at 500 °C. The corresponding electrical characterizations clearly demonstrate that the SiC nanowire based PD devices can be regarded as a promising candidate for UV PDs. The PDs can exhibit the excellent performances of fast, high sensitivity, linearity, and stable response, which can thus achieve on-line monitoring of weak UV light. Furthermore, the SiC nanowire-based PDs enable us to fabricate detectors working under high temperature as high as 150 °C. The high photosensitivity and rapid photoresponse for the PDs can be attributed to the superior single crystalline quality of SiC nanowires and the ohmic contact between the electrodes and nanowires.

In this study, the dielectrophoretic processes of SiC nanowires suspended in three typical solvents, (highly purified water, ethanol and isopropanol) were systematically investigated. Optical microscope and SEM characterizations were used to observe the order of SiC nanowires on the surface of gold microchannels. The gold microchannels were induced by Ac dielectrophoresis of the corresponding dispersion solutions of SiC nanowires, with a concentration of 0.1 mg/mL. The study shows that the dielectrophoresis process is an effective way of synthesizing highly oriented SiC nanoarrays using isopropanol solution. The results also show that the arrangement of SiC nanowires on the interdigital electrode configuration not only depend on the kind of solvent used, but also on the applied frequency (1000 Hz∼1 MHz) and voltage (1 V∼20 V).

We report, for the first time, the growth of p-type 6H-SiC nanowires with a unique triangular prism shape via the pyrolysis of polymeric precursors. The resultant wires were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The triangular prism-shaped SiC nanowires are averagely sized at ∼700 nm in edge widths with lengths of up to tens of microns. The wires are single-crystalline with 1 at% Al dopants and grown along the direction of [102]. A mechanism based on a typical vapor–liquid–solid (VLS) process was discussed for the growth of the 6H-SiC wires. Intense visible photoluminescence was observed with two respective strong emission peaks centered at 2.4 and 3.1 eV, suggesting that the p-type 6H-SiC wires could be useful in the fabrication of optoelectronic nanodevices.

Low-dimension semiconductor nanostructures were successfully synthesized by a fast, simple, and low-cost microwave method. By heating raw materials under microwave irradiation and controlled conditions, diverse nanostructures for semiconducting oxides and carbides were synthesized without extra metal catalysts. In this paper, flower-like and net structural oxide and carbide semiconductors in nanoscale have been studied in detail. Structural, morphological, and elemental analysis revealed that the as-synthesized nanostructures were highly pure and structurally uniform. The possible growth mechanisms of these nanostructures were preliminarily discussed. The temperature and the gas-phase supersaturation in their growing processes have important effects on their morphologies. The unique synthesis method may open a new way for the fabrication of self-assembled multidimensional structures, which are expected to find a wide range of important applications in nanodevices and nanocomposites.

We developed and validated a robust marker toolkit for high-throughput and cost-effective screening of a large number of functional genes in wheat. Functional markers (FMs) are the most valuable markers for crop breeding programs, and high-throughput genotyping for FMs could provide an excellent opportunity to effectively practice marker-assisted selection while breeding cultivars. Here we developed and validated kompetitive allele-specific PCR (KASP) assays for genes that underpin economically important traits in bread wheat including adaptability, grain yield, quality, and biotic and abiotic stress resistances. In total, 70 KASP assays either developed in this study or obtained from public databases were validated for reliability in application. The validation of KASP assays were conducted by (a) comparing the assays with available gel-based PCR markers on 23 diverse wheat accessions, (b) validation of the derived allelic information using phenotypes of a panel comprised of 300 diverse cultivars from China and 13 other countries, and (c) additional testing, where possible, of the assays in four segregating populations. All KASP assays being reported were significantly associated with the relevant phenotypes in the cultivars panel and bi-parental populations, thus revealing potential application in wheat breeding programs. The results revealed 45 times superiority of the KASP assays in speed than gel-based PCR markers. KASP has recently emerged as single-plex high-throughput genotyping technology; this is the first report on high-throughput screening of a large number of functional genes in a major crop. Such assays could greatly accelerate the characterization of crossing parents and advanced lines for marker-assisted selection and can complement the inflexible, high-density SNP arrays. Our results offer a robust and reliable molecular marker toolkit that can contribute towards maximizing genetic gains in wheat breeding programs.

Silicon-on-insulator (SOI) rib waveguides with residual sidewall roughness were achieved through inductive coupled plasma reactive ion etching (ICPRIE) process. Sidewall roughness is the dominant scattering loss source. Conventional ICPRIE could result in the sidewall ripples derived from the etch/deposition cycle steps. Mixed ICPRIE process and hydrogen annealing were used to improve the sidewall roughness of SOI rib waveguides and eliminate the sidewall ripples. Scan electron microscope and atomic force microscope were used to demonstrate the surface profiles of the sidewall. The results indicated that the sidewall roughness could be low down to 0.3 nm level by optimization and combination of these two techniques and the ripples disappeared. According to the scattering theory developed by Payne and Lacey, the scattering loss could be reduced to below 0.01 dB/cm.

A self-aligned two-mask lithography process was used to define silicon-on-insulator rib waveguides and corner mirrors, which were etched using inductively coupled plasma reactive ion etching. Atomic force microscopy was used to directly measure the surface morphology of the corner mirrors for the first time. The low-temperature ultrahigh vacuum annealing was used to smooth the corner mirror surface. After annealing, the ripples of the corner mirror disappeared, and the root-mean-square roughness of the mirror surface was reduced to 9.1 nm.

The optical properties of heavily Al-doped single-crystal Si3N4 nanobelts are investigated by measuring their absorption, photoluminescence, and photoluminescence excitation spectra. The results suggest that the doped Si3N4 exhibit two absorptions at 2.5 and 4.2 eV, instead of absorption at 5.0 eV in the pure Si3N4. The doped nanobelts show light emissions in a range of 1.4 to 3.6 eV, which is red-shifted as compared with that of pure Si3N4 nanobelts. These results are ascribed to the unique doping mechanism of Al, which generates two types of defects.

Novel P‐doped SiC flexible field emitters are developed on carbon fabric substrates, having both low E to of 1.03–0.73 Vμm−1 up to high temperatures of 673 K, and extremely high current emission stability when subjected to different bending states, bending circle times as well as high temperatures (current emission fluctuations are typically in the range ±2.1%–3.4%).

The density of the nanowires is one of the key issues for their field emission (FE) properties of the nanoarrays, since it plays an important role on the electron emission sites and field screening effect. Here, we reported the nanowire-density-dependent FE properties of the n-type 3C-SiC nanoarrays. The highly oriented and large-scale SiC nanoarrays were grown on the 6H-SiC wafer via pyrolysis of polyureasilazane by adjusting the thicknesses of Au films used as the catalysts. The densities of the nanoarrays were tunable to be ∼2.9 × 107, ∼4.0 × 107, and ∼5.7 × 107 nanowires/cm2 by controlling the Au film thicknesses of 50, 70, and 90 nm, respectively. The measured FE characteristics disclosed that the turn-on fields of the samples could be tailored to be of ∼1.79, 1.57, and 1.95 V/μm with the increase of the densities, suggesting that a suitable nanowire density could favor the enhanced electron emission from the SiC nanoarrays with improved emission sites and limited field screening effects.

Flexible field emission (FE) emitters, whose unique advantages are lightweight and conformable, promise to enable a wide range of technologies, such as roll-up flexible FE displays, e-papers and flexible light-emitting diodes. In this work, we demonstrate for the first time highly flexible SiC field emitters with low turn-on fields and excellent emission stabilities. n-Type SiC nanoneedles with ultra-sharp tips and tailored N-doping levels were synthesized via a catalyst-assisted pyrolysis process on carbon fabrics by controlling the gas mixture and cooling rate. The turn-on field, threshold field and current emission fluctuation of SiC nanoneedle emitters with an N-doping level of 7.58 at.% are 1.11 V μm−1, 1.55 V μm−1 and 8.1%, respectively, suggesting the best overall performance for such flexible field emitters. Furthermore, characterization of the FE properties under repeated bending cycles and different bending states reveal that the SiC field emitters are mechanically and electrically robust with unprecedentedly high flexibility and stabilities. These findings underscore the importance of concurrent morphology and composition controls in nanomaterial synthesis and establish SiC nanoneedles as the most promising candidate for flexible FE applications. Spiky silicon carbide (SiC) ‘nanoneedles’ can improve light emission from e-paper and other bendable electronic devices. Flexible field-emission displays are an emerging technology in which tiny conductive tips grown on lightweight, rollable surfaces generate intense light. Significant manufacturing- and materials-related obstacles, however, have limited their application. Now, a team led by Tom Wu from King Abdullah University of Science and Technology in Saudi Arabia and Weiyou Yang from Ningbo University of Technology in China investigated how SiC — a compound with notable stiffness and stablity — performed as a field emitter by catalytically synthesising this material into nanoscale needles with ultrasharp tips and controllable doping levels on a carbon fabric surface. Their experiments showed that the SiC nanoneedles had low ‘turn-on’ field requirements and minimal emission fluctuations even after repeated bending cycles, thanks to their impressive mechanical robustness. We demonstrated for the first time highly flexible N-doped SiC nanoneedle field emitters with low turn-on fields and excellent emission stabilities. The characterizations of their field emission properties under repeated bending cycles and different bending states confirmed that such emitters are mechanically and electrically robust. These findings underscore the importance of concurrent morphology and composition controls in nanomaterial synthesis and establish SiC nanoneedles as the most promising candidate for flexible FE applications.

Understanding the roles of contacts and interfaces between metals and semiconductors is critically important for exploring nanostructure-based nanodevices. The present study shed some light on the dominated mechanism of size-dependent carrier transfer in the Schottky barrier diodes configured by the Pt-Ir/Si3N4-nanobelt/graphite (metal-semiconductor-metal (MSM)) sandwiched structure via a conductive atomic force microscopy using nanobelts with various thicknesses. The observed I-V behaviors suggested that the charge transports under the low and high biases were dominated by the reverse-biased Schottky barrier and space-charge-limited current (SCLC), respectively. The intermediate region between the low and high biases presented the transition between the Ohmic and SCLC behaviors, in which the ≡Si and =N dangling bonds acted as the defects within the Si3N4 nanobelt surface are predominant in the charge transfer.

We demonstrate a strategy for the growth of Mn2+ ion doped cadmium based II–VI semiconductor quantum dots (QDs) with a designed buffer layer of ZnS (MnS/ZnS/CdS or Mn:CdS QDs), which aims to meet the challenge of obtaining highly efficient and well-resolved Mn2+ ion emission. First, small, high quality MnS cores are obtained by using thiols to replace conventional alkyl amines as capping ligands. Then a buffer layer of ZnS with a tailored thickness is introduced to the QDs before the growth of CdS shells to reduce the size mismatch between the Mn2+ (dopant) and Cd2+ (host) ions. The fabricated MnS/ZnS/CdS core/shell QDs exhibit a high PL QY of up to 68%, which is the highest ever reported for any type of Mn2+ ion doped cadmium based II–VI semiconductor QD. The photoluminescence (PL) of the QDs consists of well-resolved Mn2+ ion emission without any detectable emission from the CdS band edge or surface defects. In addition, our MnS/ZnS/CdS QDs cannot only be made water-soluble, but can also be coated by ligands with short carbon chain lengths, nearly without cost to the PL QY, which could make them strong candidates for practical applications in biology/biomedicine and opto/electronic devices.

In this study, we demonstrate the unconventional vapor–liquid–solid (VLS) growth of amorphous SiO2 nanooctopuses. The SiO2 nanooctopuses were successfully synthesized by a simple water-assisted reaction on Si wafers. The obtained aggregates have been systematically characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. A novel VLS model has been proposed for the growth of SiO2 nanooctopuses based on the experimental observations and characterizations. The amorphous SiO2 nanooctopuses emit stable violet-blue light, implying their potential applications in photoelectronic devices.