High-Performance Sensor Based on Thin-Film Metallic Glass/Ultra-nanocrystalline Diamond/ZnO Nanorod Heterostructures for Detection of Hydrogen Gas at Room Temperature.

This article outlines a novel material to enable the detection of hydrogen gas. The material combines thin-film metallic glass (TFMG), ultra-nanocrystalline diamond (UNCD), and ZnO nanorods (ZNRs) and can be used as a device for effective hydrogen gas sensing. Three sensors were fabricated by using combinations of pure ZNRs (Z), UNCD/ZNRs (DZ), and TFMG/UNCD/ZNRs (MDZ). The MDZ device exhibited a performance superior to the other configurations, with a sensing response of 34 % under very low hydrogen gas concentrations (10 ppm) at room temperature. Remarkably, the MDZ-based sensor exhibits an ultra-high sensitivity of 60.5 % under 500 ppm H2 . The MDZ sensor proved very fast in terms of response time (20 s) and recovery time (35 s). In terms of selectivity, the sensors were particularly suited to hydrogen gas. The sensor achieved the same response performance even after two months, thereby demonstrating the superior stability. It is postulated that the superior performance of MDZ can be attributed to defect-related adsorption as well as charge carrier density. This paper also discusses the respective energy band models of these heterostructures and also the interface effect on the gas sensing enhancements. The results indicate that the proposed hybrid TFMG/UNCD/ZNRs nanostructures could be utilized as high-performance hydrogen gas sensors.

Bio-industrial Waste Silk Fibroin Protein and Carbon Nanotube-Induced Carbonized Growth of One-Dimensional ZnO-based Bio-nanosheets and their Enhanced Optoelectronic Properties.

High performance UV/Visible photodetectors are successfully fabricated from ZnO/fibroin protein-carbon nanotube (ZFPCNT ) composites using a simple hydrothermal method. The as-fabricated ZnO nanorods (ZnO NRs) and ZFPCNT nanostructures were measured under different light illuminations. The measurements showed the UV-light photoresponse of the as-fabricated ZFPCNT nanostructures (55,555) to be approximately 26454 % higher than that of the as-prepared ZnO NRs (210). This photodetector can sense photons with energies considerably smaller (2.75 eV) than the band gap of ZnO (3.22 eV). It was observed that the finest distribution of fibroin and CNT into 1D ZnO resulted in rapid electron transportation and hole recombination via carbon/nitrogen dopants from the ZFPCNT . Carbon dopants create new energy levels on the conduction band of the ZFPCNT , which reduces the barrier height to allow for charge carrier transportation under light illumination. Moreover, the nitrogen dopants increase the adsorptivity and amount of oxygen vacancies in the ZFPCNT so that it exhibits fast response/recovery times both in the dark and under light illumination. The selectivity of UV light among the other types of illumination can be ascribed to the deep-level energy traps (ET ) of the ZFPCNT . These significant features of ZFPCNT lead to the excellent optical properties and creation of new pathways for the production of low-cost semiconductors and bio-waste protein based UV/Visible photodetectors.

Fast Photoresponse and Long Lifetime UV Photodetectors and Field Emitters Based on ZnO/Ultrananocrystalline Diamond Films.

We have designed photodetectors and UV field emitters based on a combination of ZnO nanowires/nanorods (ZNRs) and bilayer diamond films in a metal-semiconductor-metal (MSM) structure. The ZNRs were fabricated on different diamond films and systematic investigations showed an ultra-high photoconductive response from ZNRs prepared on ultrananocrystalline diamond (UNCD) operating at a lower voltage of 2 V. We found that the ZNRs/UNCD photodetector (PD) has improved field emission properties and a reduced turn-on field of 2.9 V µm(-1) with the highest electron field emission (EFE) by simply illuminating the sample with ultraviolet (UV) light. The photoresponse (Iphoto /Idark ) behavior of the ZNRs/UNCD PD exhibits a much higher photoresponse (912) than bare ZNRs (229), ZNRs/nanocrystalline diamond (NCD; 518), and ZNRs/microcrystalline diamond (MCD; 325) under illumination at λ=365 nm. A photodetector with UNCD films offers superior stability and a longer lifetime compared with carbon materials and bare ZNRs. The lifetime stability of the ZNRs/UNCD-based device is about 410 min, which is markedly superior to devices that use bare ZNRs (92 min). The ZNRs/UNCD PD possesses excellent photoresponse properties with improved lifetime and stability; in addition, ZNRs/UNCD-based UV emitters have great potential for applications such as cathodes in flat-panel displays and microplasma display devices.

Efficiency improvement of silicon nanostructure-based solar cells.

Solar cells based on a high-efficiency silicon nanostructure (SNS) were developed using a two-step metal-assisted electroless etching (MAEE) technique, phosphorus silicate glass (PSG) doping and screen printing. This process was used to produce solar cells with a silver nitrate (AgNO3) etching solution in different concentrations. Compared to cells produced using the single MAEE technique, SNS-based solar cells produced with the two-step MAEE technique showed an increase in silicon surface coverage of ~181.1% and a decrease in reflectivity of ~144.3%. The performance of the SNS-based solar cells was found to be optimized (~11.86%) in an SNS with a length of ~300 nm, an aspect ratio of ~5, surface coverage of ~84.9% and a reflectivity of ~6.1%. The ~16.8% increase in power conversion efficiency (PCE) for the SNS-based solar cell indicates good potential for mass production.

Rice-straw-like structure of silicon nanowire arrays for a hydrogen gas sensor.

A rice-straw-like silicon nanowire (SiNW) array was developed for hydrogen gas sensing applications. The straight-aligned SiNW array sensor was first fabricated by the metal-assisted electroless etching (MAEE) technique. Rice-straw-like SiNW arrays were formed using a repeated MAEE technique. Hydrogen sensing characteristics were measured for gas concentrations from 20 to 1000 ppm at room temperature. The rice-straw-like SiNW-array-based hydrogen gas sensor performed with low noise and a high response (232.5%) for 1000 ppm hydrogen gas. It was found that the rice-straw-like SiNW-array hydrogen gas sensor had a much better response (approximately 2.5 times) than the straight-aligned SiNW-array sensor. The rice-straw-like SiNW-array structure effectively increased the surface area and the concentration of silicon oxide, which provided additional binding sites for gas molecules. Thus, the rice-straw-like SiNW-array-based hydrogen gas sensor possessed good sensing properties and has the potential for mass production of sensing devices.

Controllable Doping Characteristics for WSxSey Monolayers Based on the Tunable S/Se Ratio.

Transition metal dichalcogenides (TMDs) have attracted much attention because of their unique characteristics and potential applications in electronic devices. Recent reports have successfully demonstrated the growth of 2-dimensional MoSxSey, MoxWyS2, MoxWySe2, and WSxSey monolayers that exhibit tunable band gap energies. However, few works have examined the doping behavior of those 2D monolayers. This study synthesizes WSxSey monolayers using the CVD process, in which different heating temperatures are applied to sulfur powders to control the ratio of S to Se in WSxSey. Increasing the Se component in WSxSey monolayers produced an apparent electronic state transformation from p-type to n-type, recorded through energy band diagrams. Simultaneously, p-type characteristics gradually became clear as the S component was enhanced in WSxSey monolayers. In addition, Raman spectra showed a red shift of the WS2-related peaks, indicating n-doping behavior in the WSxSey monolayers. In contrast, with the increase of the sulfur component, the blue shift of the WSe2-related peaks in the Raman spectra involved the p-doping behavior of WSxSey monolayers. In addition, the optical band gap of the as-grown WSxSey monolayers from 1.97 eV to 1.61 eV is precisely tunable via the different chalcogenide heating temperatures. The results regarding the doping characteristics of WSxSey monolayers provide more options in electronic and optical design.

The Efficiency Study of Graphene Synthesis on Copper Substrate via Chemical Vapor Deposition Method with Methanol Precursor.

Few-layer graphene was successfully synthesized on copper foil via chemical vapor deposition with methanol as a carbon source. This was confirmed by optical microscopy observation, Raman spectra measurement, I2D/IG ratio calculation, and 2D-FWHM value comparisons. Monolayer graphene was also found in similar standard procedures, but it required higher growth temperature and longer time periods. The cost-efficient growth conditions for few-layer graphene are thoroughly discussed via TEM observation and AFM measurement. In addition, it has been confirmed that the growth period can be shortened by increasing growth temperature. With the H2 gas flow rate fixed at 15 sccm, few-layer graphene was synthesized at the lower growth temperature of 700 °C in 30 min, and at 900 °C growth temperature in only 5 min. Successful growth was also achieved without adding hydrogen gas flow; this is probably because H2 can be induced from the decomposition of methanol. Through further defects study of few-layer graphene via TEM observation and AFM measurement, we tried to find possible ways for efficiency and quality management in graphene synthesis in industrial applications. Lastly, we investigated graphene formation after pre-treatment with different gas compositions, and found that gas selection is a crucial factor for a successful synthesis.

Growth of Graphitic Carbon Nitride-Incorporated ZnO Nanorods on Silicon Pyramidal Substrates for Enhanced Hydrogen Sensing Applications.

Monitoring the hydrogen gas (H2) level is highly important in a wide range of applications. Oxide-carbon hybrids have emerged as a promising material for the fabrication of gas sensors for this purpose. Here, for the first time, graphitic carbon nitride (g-C3N4)-doped zinc oxide nanorods (ZNRs) have been grown on silicon (Si) pyramid-shaped surfaces by the facile hydrothermal reaction method. The systematic material analyses have revealed that the g-C3N4 nanostructures (NS) have been consistently incorporated into the ZNRs on the pyramidal silicon (Py-Si) surface (g-C3N4-ZNRs/Py-Si). The combined properties of the present structure exhibit an excellent sensitivity (∼53%) under H2 gas exposure, better than that of bare ZNRs (12%). The results revealed that the fine incorporation of g-C3N4 into ZNRs on the Py-Si surface improves the H2 gas sensing properties when compared to that of the planar silicon (Pl-Si) surface. The doping of g-C3N4 into ZNRs increases the electrical conductivity through its graphene-like edges (due to the formation of delocalized bonds in g-C3N4 during carbon self-doping), as revealed by FESEM images. In addition, the presence of defects in g-C3N4 induces the gas adsorption properties of ZnO through its active sites. Moreover, the integration of the 1D structure (g-C3N4-ZNRs) into a 3D pyramidal structure opens up new opportunities for low-cost H2 gas sensing at room temperature. It is an easy way to enhance the gas sensing properties of ZNRs at room temperature, which is desirable for practical H2 sensor applications.

Gas ionization sensors with carbon nanotube/nickel field emitters.

Gas ionization sensors based on the field emission properties of the carbon nanotube/nickel (CNT/Ni) field emitters were first developed in this work. It is found that the breakdown electric field (E(b)) slightly decreases from 2.2 V/microm to 1.9 V/microm as the pressure of H2 gas increases from 0.5 Torr to 100 Torr. On the contrary, E(b) obviously increases from 2.9 V/microm to 6.5 V/microm as O2 gas pressure increases from 0.5 Torr to 100 Torr. This may be explained by the depression of the electron emission that caused by the adsorption of the O2 gas on the CNT emitters. The Raman spectra of the CNT/Ni emitters also show that more defects were generated on the CNTs after O2 gas sensing. The Joule heating effect under high current density as performing H2 sensing was also observed. These effects may contribute the pressure dependence on the breakdown electric field of the CNT/Ni gas ionization sensors.

The effect of tetrafluoromethane plasma post-treatment on the electrical property of tungsten oxide nanowires.

The effects of tetrafluoromethane (CF4) plasma on the surface morphology, chemical compositions, and electrical property of tungsten oxide (W18O49) nanowires are investigated. The nanostructured tungsten oxide nanowires with average length of 250-350 nm were self-catalytically grown on Si substrate. By post-treatment with CF4 plasma for 10 min, the W18O49 nanowires on the substrate showed the highest current response. Longer CF4 plasma post-treatment time demonstrated higher etching effect which demolished the nanowires and resulted in lower conductivity of the samples. The disintegration of the W18O49 nanowires layer after CF4 plasma treatment, revealed physically by the decrease of the average thickness and chemically by the decrease of XRD peak ratio (I 23.0/I 26.0), was closely related to the overall electrical performance. The etching effect was further reveled by Raman spectra showing the evolution of O-W-O and W=O characteristics with the increased post-treatment time. Moreover, the improvement of the electrical property of W18O49 nanowires was elucidated by the exposure rate to explain the mechanism of plasma post treatment in three stages: passivation, degradation and ablation. The maximum exposure rate, corresponding to the maximum conductivity, was achieved by 10 min of CF4 plasma treatment. The time-differentiated exposure analyses confirmed the evolution of resistance of W18O49 nanowires on Si with different post-treatment time which supported the results of surface characterizations.

Role of Nanodiamond Grains in the Exfoliation of WS2 Nanosheets and Their Enhanced Hydrogen-Sensing Properties.

Herein, for the first time, a combination of detonation nanodiamond (DND)-tungsten disulfide (WS2) was devised and studied for its selective H2-sensing properties at room temperature. DND-WS2 samples were prepared by a sonication-assisted (van der Waals interaction) liquid-phase exfoliation process in low-boiling solvents with DND as a surfactant. The samples were further hydrothermally treated in an autoclave under high pressure and temperature. The as-prepared samples were separated as two parts named DND-WS2 BH (before hydrothermal) and DND-WS2 AH (after hydrothermal). The exfoliated bilayer to few-layer DND-doped WS2 nanosheets were confirmed by ultraviolet-visible spectra, atomic force microscopy, and transmission electron microscopy studies. It was observed that the DND powder not only acted as a surfactant but also doped and expanded on WS2 nanosheets. The difference between samples BH and AH treatment was further investigated using Raman spectroscopy. The WS2 and DND-WS2 samples on SiO2/Si were fabricated using a sputtered Pd/Ag interdigitated electrode and utilized for H2 gas-sensing measurements. Surprisingly, the DND-WS2 exhibits an ultrahigh sensor response of 72.8% to H2 at 500 ppm when compared to only 9.9% for WS2 alone. Also, the DND-WS2 shows a fast response/recovery time, high selectivity, and stability toward H2 gas. It can be attributed to the correlation of the intergrain phase of DND nanoparticles and WS2 nanosheets, which contributes to the easy transportation of charge carriers when exposed to the air and H2 gas atmosphere. Moreover, it is believed that DND-induced WS2 exfoliation might inspire future synthesis of transition metal dichalcogenides induced by DND in green solvents.

Enhancement of UV Photodetection Properties of Hierarchical Core-Shell Heterostructures of a Natural Sericin Biopolymer with the Addition of ZnO Fabricated on Ultra-Nanocrystalline Diamond Layers.

A novel self-assembled hierarchical heterostructure is derived from cocoon-derived sericin biopolymer (CSP) biowaste with ZnO deposited on ultra-nanocrystalline diamond (UNCD) substrates using a scalable chemical deposition technique. Then, high-performance long-life UV photodetectors are fabricated using this hybrid sericin, diamond, and ZnO (SDZ) nanostructure. The microstructural analysis reveals a several nanometer-thick CSP shell coated with a highly uniform ZnO nanorod (ZNR) array grown on the UNCD substrate. The CSP shell also contains columnar nanograins on top of the ZNR as well as vertical sidewalls with unique alignments. The hierarchical core-shell SDZ heterostructures reveal superior UV diode performance, with an ultrahigh UV switching ratio of 1.1 × 105 at 5 V, an increase of up to 49 900% greater than that of as-grown ZNRs (220). High UV responsivity is observed around 3.6 A W-1 under 365 nm UV light illumination. The perfect distribution of the sericin in the ZNRs on the UNCD substrates resulted in the ultrafast electron-hole recombination. The sericin dopants and the UNCD interlayer enabled the device to reach new energy levels in the conduction band, with the reduced barrier height allowing for improved charge carrier transportation during UV light illumination. It is believed that the sericin dopants and the UNCD layer increased the UV adsorptivity and the amount of conducting carbon dopants within the ZNRs was sufficient for s0tability. These noteworthy features make the SDZ heterostructures promising candidates for the fabrication of cost-efficient biopolymers and UNCD hybrid-based UV photodetectors.

Superficial Edge Effect of N2-Doped Nanodiamond on the Highly Stable Nonenzymatic Glucose Detection Properties of Dispersed Graphene Flakes/Ni Nanostructures.

In this study, we report nitrogen-doped nanodiamond (ND)-integrated crushed graphene (Gr) nanoflakes on nickel hydroxide (Ni(OH)2, named NH) nanostructures for highly stable nonenzymatic glucose sensors. A chemical vapor deposition route with a simple hydrothermal method was devised in the fabrication of ND-Gr-NH nanostructures. Thus, the results depict that the best sensitivity of 13769 µA mM-1 cm-2 was detected for Gr-NH, while NH shows 10,358 µA mM-1 cm-2. The salient improvement in the sensitivity of ND-Gr-NH is 15,431.2 µA mM-1 cm-2, with a limit of detection of 0.1 µm. The enhancement in ND-integrated Gr-NH is due to the synergistic influence of ND and graphene on NH. Furthermore, the ND-Gr-NH electrode shows a good stability (95%), while Gr-NH exhibits a stability of 82% over 21 days. In addition, the present ND-based electrode shows high selectivity toward glucose among additional interfering compounds including sodium chloride (NaCl), uric acid, and ascorbic acid. These outstanding enzymeless glucose sensing results could be ascribed to the synergistic influence that provides more active sites and further enhances the electron-transfer reaction.

Silicon nanocone arrays deposited by sputtering.

Silicon nanostructures were produced by sputter deposition of silicon in mixtures of hydrogen and argon, on the surface of a silicon substrate with dispersed gold islands, at a substrate temperature of 450 degrees C. Continuous Si films were deposited when the hydrogen concentration in the working gas was less than 50%. Silicon nanocone arrays were grown when the hydrogen concentration exceeded 50%. The lateral size of silicon nanocones increased with the deposition time. However, the length of the silicon nanocones saturated as the deposition time was increased. Mechanisms of the growth of Si nanocones by sputter deposition in mixtures of hydrogen and argon were discussed.

Interfacial Effect of Oxygen-Doped Nanodiamond on CuO and Micropyramidal Silicon Heterostructures for Efficient Nonenzymatic Glucose Sensor.

Herein, the novel strategy of copper oxide (CuO) deposited oxygen-doped nitrogen incorporated nanodiamond (NOND)/Si pyramids (Pyr-Si) heterostructure is studied for high-performance nonenzymatic glucose sensor. The combined properties of surface-modified NOND/Pyr-Si induced by different growth durations (5 to 20 min) of CuO is envisioned to improve glucose sensitivity and stability. For comparison, the same methods and parameters were deposited on the plane silicon wafers. The systematic analysis reveals the best glucose sensing properties of 15 min grown CuO/NOND/Pyr-Si based sensor, with a high sensitivity of 1993 µA mM-1 cm-2, a lower limit of detection of 0.1 µm, and a longer stability of 28 d (∼96%). In addition, the present sensor exhibits good selectivity of glucose among other analytes such as sodium chloride, ascorbic acid, uric acid, and so on. The enhancement in glucose sensing performances of the as-fabricated CuO/NOND/Pyr-Si is ascribed to the interfacial effect of NOND and the synergistic effect of CuO and NOND/Pyr-Si. Moreover, the oxygen dopant in NOND and CuO stimulates the reactive oxygen species while measuring glucose and affords rapid recovery (<2 s). This promotes fast electron kinetics in the electrocatalytic solutions, which enhances the electroactive area and thereby contributes to a high sensitivity. These salient results suggested that the as-fabricated CuO/NOND/Pyr-Si sensor is more suitable for high-performance biosensors and effective energy storage device applications.

Antigen detection with thermosensitive hydrophilicity of poly(N-isopropylacrylamide)-grafted poly(vinyl chloride) fibrous mats.

Poly(vinyl chloride) (PVC) was electrospun as fibrous mats to treat with NaN3. The secondary chlorines of PVC were modified to generate azido-terminated electrospun PVC fibrous mats (EPFMs). Sequentially, propargyl-terminated poly(N-isopropylacrylamide) (PNIPAAm) was further synthesized and grafted onto the azido-terminated EPFMs via a click reaction resulting in a scale-like structure on the fibers. The static water contact angles (SWCAs) of the grafted EPFMs reached 0 and 140° when the working temperatures were 25 and 45 °C, respectively. In contrast to the grafts on a smooth surface, the change in SWCA from 25 to 45 °C was enhanced significantly. EPFMs with PNIPAAm grafts could immobilize an antibody (antiHA), and they could be used for an immunosorbent assay. After coupling with an antigen (HRP-HA) at 80 ng mL-1 for 8 min, the hydrophobicity of EPFMs with PNIPAAm grafts disappeared completely at 45 °C. In addition, the grafted EPFMs exhibited a much more dark blue color than those without the PNIPAAm grafts. SWCA below 10° at 45 °C could be exploited as an index to determine the limit of detection (LOD) as 80 ng mL-1. The immunosorbent assay of EPFMs with PNIPAAm grafts experimentally exhibited high potential in a simple set-up for biosensing due to the unique sensitivity and selectivity of the grafted EPFMs.

Self-Assembled Hierarchical Interfaces of ZnO Nanotubes/Graphene Heterostructures for Efficient Room Temperature Hydrogen Sensors.

Herein, we report the novel nanostructural interfaces of self-assembled hierarchical ZnO nanotubes/graphene (ZNT/G) with three different growing times of ZNTs on graphene substrates (namely, SH1, SH2, and SH3). Each sample was fabricated with interdigitated electrodes to form hydrogen sensors, and their hydrogen sensing properties were comprehensively studied. The systematic investigation revealed that SH1 sensor exhibits an ultrahigh sensor response even at a low detection level of 10 ppm (14.3%) to 100 ppm (28.1%) compared to those of the SH2 and SH3 sensors. The SH1 sensor was also found to be well-retained with repeatability, reliability, and long-term stability of 90 days under hydrogenation/dehydrogenation processes. This outstanding enhancement in sensing properties of SH1 is attributed to the formation of a strong metalized region in the ZNT/G interface due to the inner/outer surfaces of ZNTs, establishing a multiple depletion layer. Furthermore, the respective band models of each nanostructure were also purposed to describe their heterostructure, which illustrates the hydrogen sensing properties. Moreover, the long-term stability can be ascribed by the heterostructured combination of ZNTs and graphene via a spillover effect. The salient features of this self-assembled nanostructure are its reliability, simple synthesis method, and long-term stability, which makes it a promising candidate for new generation hydrogen sensors and hydrogen storage materials.

Natural Biowaste-Cocoon-Derived Granular Activated Carbon-Coated ZnO Nanorods: A Simple Route To Synthesizing a Core-Shell Structure and Its Highly Enhanced UV and Hydrogen Sensing Properties.

Granular activated carbon (GAC) materials were prepared via simple gas activation of silkworm cocoons and were coated on ZnO nanorods (ZNRs) by the facile hydrothermal method. The present combination of GAC and ZNRs shows a core-shell structure (where the GAC is coated on the surface of ZNRs) and is exposed by systematic material analysis. The as-prepared samples were then fabricated as dual-functional sensors and, most fascinatingly, the as-fabricated core-shell structure exhibits better UV and H2 sensing properties than those of as-fabricated ZNRs and GAC. Thus, the present core-shell structure-based H2 sensor exhibits fast responses of 11% (10 ppm) and 23.2% (200 ppm) with ultrafast response and recovery. However, the UV sensor offers an ultrahigh photoresponsivity of 57.9 A W-1, which is superior to that of as-grown ZNRs (0.6 A W-1). Besides this, switching photoresponse of GAC/ZNR core-shell structures exhibits a higher switching ratio (between dark and photocurrent) of 1585, with ultrafast response and recovery, than that of as-grown ZNRs (40). Because of the fast adsorption ability of GAC, it was observed that the finest distribution of GAC on ZNRs results in rapid electron transportation between the conduction bands of GAC and ZNRs while sensing H2 and UV. Furthermore, the present core-shell structure-based UV and H2 sensors also well-retained excellent sensitivity, repeatability, and long-term stability. Thus, the salient feature of this combination is that it provides a dual-functional sensor with biowaste cocoon and ZnO, which is ecological and inexpensive.

High-Performance Electron Field Emitters and Microplasma Cathodes Based on Conductive Hybrid Granular Structured Diamond Materials.

High-performance diamond electron field emitters (EFEs) with extremely low turn-on field (E0 = 1.72 V/µm) and high current density (1.70 mA/cm2 at an applied field of 3.86 V/µm) were successfully synthesized by using a modified two-step microwave plasma chemical deposition process. Such emitters possess EFE properties comparable with most of carbon- or semiconductor-based EFE materials, but with markedly better lifetime stability. The superb EFE behavior of these materials was achieved owing to the reduction in the diamond-to-Si interfacial resistance and the increase in the conductivity of the bulk diamond films (HBD-400 V) via the applications of high bias voltage during the preparation of the ultrananocrystalline diamond (UNCD) primary layer and the subsequent plasma post-treatment (PPT) process, respectively. The superior EFE properties along with enhanced robustness of HBD-400 V films compared with the existing diamond-based EFE materials rendered these materials of greater potential for applications in high brightness display and multifunctional microplasma.

Few-Layer Thin-Film Metallic Glass-Enhanced Optical Properties of ZnO Nanostructures.

A few layers of Cu-based (Cu47Zr42Al7Ti4) thin-film metallic glasses (TFMGs) were sputtered on hydrothermally synthesized ZnO nanowires/glass and ZnO nanotubes/glass to fabricate UV photodetectors. The few layers of Cu-based TFMG are ultrathin at ∼0.98 nm and have a noncrystalline metal structure according to X-ray diffraction, Raman, photoluminescence, and high-temperature transmission electron microscopy verification. The photoresponse performance of the coated few-layers Cu-TFMG samples was enhanced 1680-7700% compared with the noncoated sample. The few-layers Cu-TFMG has high transmittance ∼90% in the visible band and creates a large capacitor to absorb UV photocurrent and release dark current.