Nanohole Research Articles

Multiple Stimulus Response Material Based on Sr-tcbpe MOF for Mechanochromism, Visualization Labeling, and Etching Toward TNP.

The abuse and excessive discharge of organic pollutants such as nitroaromatic compounds (NACs) have become a hot topic of concern for all humanity and society, and the development of fast, effective, and targeted technical means for detecting NACs also faces many challenges. Here, we reported a strontium-based metal-organic framework (MOF) {[Sr2(tcbpe)(H2O)4]}n (Sr-tcbpe), in which tcbpe represents deprotonated 4',4‴,4″‴,4‴‴-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1'biphenyl]-4-carboxylic acid)). In Sr-tcbpe, Sr-O polyhedron and deprotonated tcbpe4- ligand have a staggered connection to form a self-assembled three-dimensional network structure. In addition, it is found that Sr-tcbpe undergoes no luminescent color change when grinding under solvent protection, while mechanochromic fluorescence behavior is observed when grinding directly, leading to luminescent color changes from cyan to green (Sr-tcbpe-G). Additionally, Sr-tcbpe and Sr-tcbpe-G could selectively detect PNP, DNP, and TNP, and Sr-tcbpe achieves visual fluorescence sensing detection toward TNP at a limit of detection as low as 2.25 μM. Moreover, during the detection process, unexpectedly, TNP exhibits a selective etching effect on Sr-tcbpe, which could drill nano holes with different sizes on the surface area of MOF materials to a certain extent, achieving the conversion of chemical energy to mechanical energy. In addition, the successful preparation of a portable sensor Sr-tcbpe@gypsum block provides a platform for the perfect combination of mechanochromic fluorescence behavior and visualization detection toward TNP. It lays the foundation for the practical application of MOF materials in daily life.

Energies of Fröhlich surface optical phonon in Q1D nanostructures: Curvature and dielectric effects

Energy of Fröhlich surface optical (SO) phonon in quasi-one-dimensional (Q1D) nanostructures remains doubtful in terms of Raman and photoluminescence experimental data. Based on a notion of the curvature proposed, the confusion is clearly clarified. It is found that the energy interval of SO modes previously accepted in the quantum system could be further divided into two sub-intervals based on the positive and negative curvature of nanowire (NW) and nanohole (NH). Furthermore, the cutoff energy and width of energy sub-intervals in NW and NH can be modulated by altering the dielectric constant of the surrounding medium. Moreover, the physical mechanism of curvature and dielectric effects on the energies of SO phonon in NW and NH are comprehended reasonably from a perspective of electrostatic potential distribution. The calculated energies of SO modes in low-energy sub-interval are fully consistent with the Raman and PL experimental results for AlN, GaN, and InN NWs. It is predicted that SO modes of high-energy sub-interval could be observed in the NH structure. The current theoretical scheme and numerical results not only extend and deepen the knowledge of the energy of the SO phonon but also can be used in the design and development of optical and optoelectronic devices based on SO modes of Q1D nanostructures.

Optimization of Contact Resistance and DC Characteristics for AlGaN/GaN HEMTs Utilizing Sub-10 nm Nanohole Etching

In this paper, the contact resistance of AlGaN/GaN high electron mobility transistor (HEMT) was improved by introducing nanoscale hole arrays in ohmic regions, and the DC characteristics of the conventional structure and nanohole etching structure for HEMTs were measured for comparison. Sub-10 nm nanoholes were patterned on the ohmic area surface of AlGaN using electron beam lithography and a low-temperature short-time development. Various dwell times of e-beam exposure from 5 to 30 μs were investigated and the corresponding contact resistance of the nano hole etching structure and planar structure were compared by the transmission line model (TLM) method. We observed a reduced contact resistance from 1.82 to 0.47 Ω-mm by performing a dwell time of 5 μs of exposure for nanohole formation compared to the conventional structure. Furthermore, the DC characteristics demonstrate that the maximum drain current for HEMTs was enhanced from 319 to 496 mA/mm by utilizing this optimized ohmic contact. These results show that devices with sub-10 nm nanohole ohmic contacts exhibit an improved contact resistance over the conventional structure, optimizing device performance for HEMTs, including a lower on-resistance and higher maximum drain current.

Mechanically-Durable Antireflective Subwavelength Nanoholes on Glass Surfaces Using Lithography-Free Fabrication.

Traditional multilayer antireflection (AR) surfaces are of significant importance for numerous applications, such as laser optics, camera lenses, and eyeglasses. Recently, technological advances in the fabrication of biomimetic AR surfaces capable of delivering broadband omnidirectional high transparency combined with self-cleaning properties have opened an alternative route toward realization of multifunctional surfaces which would be beneficial for touchscreen displays or solar harvesting devices. However, achieving the desired surface properties often requires sophisticated lithography fabrication methods consisting of multiple steps. In the present work, we show the design and implementation of mechanically robust AR surfaces fabricated by a lithography-free process using thermally dewetted silver as an etching mask. Both-sided nanohole (NH) surfaces exhibit transmittance above 99% in the visible or the near-infrared ranges combined with improved angular response at an angle of incidence of up to θi = 60°. Additionally, the NHs demonstrate excellent mechanical resilience against repeated abrasion with cheesecloth due to favorable redistribution of the shearing mechanical forces, making them a viable option for touchscreen display applications.

Tip-based Lithography with a Sacrificial Layer.

The fabrication of a highly controlled gold (Au) nanohole (NH) array via tip-based lithography is improved by incorporating a sacrificial layer-a tip-crash buffer layer. This inclusion mitigates scratches during the nano-indentation process by employing a 300nm thick poly(methyl methacrylate) layer as a sacrificial layer on top of the Au film. Such a precaution ensures minimal scratches on the Au film, facilitating the creation of sub-50nm Au NHs with a 15nm gap between the Au NHs. The precision of this method exceeds that of fabricating Au NHs without a sacrificial layer. Demonstrating its versatility, this Au NH array is utilized in two distinct applications: as a dry etching mask to form a molybdenum disulfide hole array and as a catalyst in metal-assisted chemical etching, resulting in conical-shaped silicon nanostructures. Additionally, a significant electric field is generated when Au nanoparticles (NPs) are placed within the Au NHs. This effect arises from coupling electromagnetic waves, concentrated by the Au NHs and amplified by the Au NPs. A notable result of this configuration is the enhancement factor of surface-enhanced Raman scattering, which is an order of magnitude greater than that observed with just Au NHs and Au NPs alone.

Sensitivity Analysis of SPR Nano Hole Array Structure for Lab-On-Chip Application

In this work sensitivity analysis of surface plasmon resonance based nano hole array (SPR NHA) is reported. SPR NHA are suitable for lab-on-a-chip applications. These devices work in three different modes, namely intensity mode, phase mode, and angular mode. In this work intensity mode analysis is used. The SPR NHA consisting of gold metal and silicon dioxide substrate dielectric material is used. Gold material is widely used in SPR sensors due to its excellent optical properties, high electrical conductivity and bio-compatibility. The Finite Difference Time Domain (FDTD) method is used for the simulation and analysis. An optical source at a wavelength of 675 nm is used for the analysis and simulation. The structure of the proposed SPRNHA consists of Substrate which is made of silicon di oxide dielectric material and a thin layer of gold is deposited on the substrate having thickness 0.1 µm. The nano hole array is etched on the gold layer. The pitch of the NHA is 0.6 µm and diameter of each hole is 0.2 µm. The diameter of the holes present in NHA is 0.2 µm. The sensitivity of the proposed device for different analytes such as albumin, RBC and hemoglobin is determined. The maximum sensitivity of 298.35 nm/RIU is achieved for the proposed device. The results obtained shows that the sensor has better sensitivity and suitable for use in lab-on-a-chip applications.

Review of: "Power of nano holes in (electric nano supercapacitors)"

Review of: "Power of nano holes in (electric nano supercapacitors)"

Novel insight into the physics of short-range ordered nanoholes: Newly defined lattice model and transmittance response related to lattice parameters and ordering evolution

This paper presents unforeseen conceptualization, methods and results on the physics of short-range ordered (SRO) gold nanohole (NH) distributions, fabricated by a recent protocol developed by the authors. The straightforward extension to SRONHs of the existing knowledge about periodic NH arrays is confuted and an alternative interpretative picture is proposed and discussed based on three main advancements. First, it is set up a so-called short-range lattice (SR-Lat) method to rigorously and fully characterize the coverage-dependent short-range ordering through the determination of local coordination and periodicity length (aSR) of the NH arrangement. Second, it is demonstrated the failure of the common assumption that the average center-to-center distance of nearest neighbor colloids/nanoholes (dNN) is the characteristic length-scale of SRONHs and aSR is set as the proper periodicity parameter. Third, a predictive relationship is formulated between the wavelength of the propagating plasmon modes and aSR that highlights inherent differences with respect to periodic NHs.The presented results lay rigorous foundation for studying systems with correlated diosrdering in general and for making predictions useful not only in design and applications of SRONHs, but also on the surface physics in the photonics and sensing fields.

Investigation of perfect narrow-band absorber in silicon nano hole array

In this paper, we proposed a triple layer structure consisting of the bottom silver layer, thin silicon oxide space layer, and ultrathin semiconductor silicon film with nano hole array achieving three absorption peaks with narrow band. The absorption spectrum can be easily controlled by adjusting the structural parameters including the radius and period of the nano hole array, and the maximal absorption can reach 99.0% and the narrowest full width of half maximum can reach about 6.5 nm in theory. We also clarified the physical mechanism of the proposed structure in details by finite-difference time-domain simulation, in which the three narrow band perfect adsorption peaks can be attributed to electric dipole resonance, magnetic dipole resonance and plasmonic resonance respectively. At the same time, we used a low-cost nanosphere lithography method to fabricate the proposed nano hole array in large area. In experiment, the absorption peak of the proposed triple layer structure can reach up to 98.3% and the narrowest full width of half maximum can reach up to about 10.1 nm. The highest quality factor Q can reach up to 98.4. This work can open a new avenue for high-quality factor narrow band perfect absorption using ultrathin semiconductor film and benefit for many fields such as infrared sensors, plasmonic filters, and hyperspectral imaging.

CMOS Image Sensor With Micro–Nano Holes to Improve NIR Optical Efficiency: Holes on Top Surface Versus on Bottom

CMOS Image Sensor With Micro–Nano Holes to Improve NIR Optical Efficiency: Holes on Top Surface Versus on Bottom

OLEDs on planarized light outcoupling-enhancing structures in plastic

Light extraction from OLEDs remains a challenge. While consumer demand for OLEDs in display technology continues to grow as prices decline, commercial use of OLEDs in solid state lighting (SSL) applications is lagging due to low light extraction, which results in low efficiency. Previous studies have been directed toward increasing the light extraction factor η out , but cost-effective approaches that will enable high throughput and potential upscaling, as well as elucidation of the extraction process, are still lagging. One promising approach is the use of buried light extraction enhancing patterns that are planarized with a high refractive index (RI) layer. When adding substrate mode extracting means, the highest external quantum efficiencies (EQEs) were achieved using a complex approach of planarized vacuum nano holes. Here we present η out -enhancing planarized extraction structures (PES) in plastic. While plastic substrates currently present long-term stability issues and other drawbacks, as we show, they provide a tool for simple, inexpensive, and rapid generation of various enhancing structures that importantly can be transferred to the preferred rigid and flexible glass substrates. Moreover, plastic substrates are attractive for biomedical applications. The successful structures we present are easily scalable periodic corrugations, e.g., with pitch a ∼4.25 μm and pitch/depth ratio a/h ∼ 2.4 planarized by a layer of RI ∼1.9, resulting in maximal EQEs exceeding 60% for a green OLED and 48.5% for a white OLED. Comparable increased EQEs were achieved for structures with a ∼15 and 16 μm, and a/h ∼2.1 and 4, respectively. Enhanced extraction was also observed with a very simply fabricated quasiperiodic nanohole array, and surprisingly, with a random shallow design. The latter is at variance with simulations based on diffraction only. Results are discussed in terms of a , h , and structural parameters together with scattering matrix simulations to assess the effect of various PES parameters and the nanoparticle-embedded planarizing layer on η out . The experiments and simulations indicate contributions of diffraction, reflection, and scattering to EQE enhancement. • Light outcoupling-enhancing planarized extraction structures (PES) in plastic. • A tool for simple, inexpensive, & rapid generation of various enhancing structures. • Useful PES: periodic patterns, quasiperiodic nanohole array, random shallow design. • EQEs achieved: 61% - green OLED; 48.5% - white OLED. • Experiment & theory: enhanced EQEs due to diffractive & diffuse light scattering.

Light scattering by plasmonic disks and holes arrays: different or the same?

We suggest a strategy for designing regular 2D arrays of nanoholes (NHs) in metal films with far-field scattering properties similar to that of regular 2D arrays of nanodisks (NDs) with the same periodicity. Full-wave simulations for perfectly conducting, Ag and Au NDs and respectively designed arrays of NHs demonstrate a minor difference between far-field properties either at wavelengths corresponding to Wood–Rayleigh anomalies of the arrays or in a broad wavelength range, depending on the array periodicity and sizes of NDs (NHs). Our results have broad implications in plasmon-enhanced-driven applications, including optoelectronic and photovoltaic devices, where the NH arrays are preferable to be fabricated for nano-structured optics.

Laser induced nano-hole for high throughput fabrication of silver doped chalcogenide metasurfaces

We report the potential method for high throughput chalcogenide metasurface fabrication by using focused 632.8 nm laser induced nano-hole effect in the silver doped Ge28Sb12Se60 film. Generally, laser induced dewetting effect is hard to realize in thin Ge28Sb12Se60 films, however with the assistance of silver doping, the randomly distributed nano holes can be acquired in the dewetted region. The higher the silver concentration, the easier the laser induced nano-hole effect is, but much higher silver concentration like 47.8% will suppress the laser induced nano-hole effect due to the photocrystallisation. The nano holes can be enlarged and further connect with adjacent ones by increasing the output laser power, thus the morphology of the laser induced nano holes can be flexibly manipulated. Our findings are beneficial in high-throughput fabrication of chalcogenide metamaterial.

Investigation on thermal induced implant of metallic nanoparticles into substates: Catalyzed decomposition or surface liquefaction?

Metallic nanoparticle implant while thermal processing has been widely reported and brilliantly applied in surface modification. However, arguments remain on the basics of etching mechanism in terms of the main drive force. In this work, nanohole (NH) formation is investigated on quartz by assistant of Cu nanoparticles. With confocal morphological and chemical characterizations by photo-induced force microscopy, the evidence of Cu-Si alloy formation is found thus strongly suggests the substrate decomposition can play an important role in NH fabrication. Based on the results obtained with temperature gradient, the two-regime evolution process is observed.

Photo‐Induced Discoloration and the Corresponding Mechanism of Benzotrifuroxan under UV Irradiation

AbstractBenzotrifuroxan (BTF) as a powerful and hydrogen‐free explosive discolors under UV irradiation, but the process remains unclear. Herein, we comprehensively investigated the photochemical process and mechanism of BTF under UV irradiation. A pink color is observed in BTF after irradiation with 365‐nm light, while BTF becomes brown by 254‐nm light. Besides BTF, compound 1 is detected by ultrahigh‐performance liquid chromatography after UV irradiation. Compound 1 is prone to be yielded under 254‐nm irradiation compared to 365‐nm irradiation. Meanwhile, it is easier for the formation of compound 1 in BTF solution rather than solid BTF. Additionally, a small amount of compound 2 is found in BTF solution after 254‐nm irradiation over 120 min. A new photodegradation pathway of BTF is proposed through high‐resolution mass spectrometry. Compound 1 is produced as the main product through the isomerization of the N‐oxide of BTF, and BTF also loses NO to yield compound 2. Through the analysis of scanning electron microscopy, BTF exhibits different crystal structures between 365‐nm irradiation and 254‐nm irradiation. Nano holes are widely observed in solid BTF after 365‐nm irradiation, but these holes disappear under 254‐nm irradiation. Thus, the differences originating from the content of compound 1 and the crystal structure of BTF may lead to the discoloration of BTF under UV irradiation.

The Scattering of SH Wave in a Nano Hole Embedded the Infinite Inhomogeneous Medium

Scattering of the shear waves by a nano-sized cylindrical hole embedded the inhomogeneous is investigated in this study. The Helmholtz equation with a variable coefficient is transformed the standard Helmholtz equation by the complex function method and the conformal mapping method. By wave function expanding method, the analytical expressions of the displacement field and stress field in the inhomogeneous medium are obtained. Considering the surface effect and using the generalized Young-Laplace equation, we obtain the boundary conditions at nano arbitrary-shaped hole, then the field equations satisfying boundary conditions are attributed to solving a set of infinite algebraic equations. Numerical results show that when the radius of the cylindrical cavity shrinks to nanometers, surface energy becomes a dominant factor that affects the dynamic stress concentration factor (DSCF) around the cylindrical cavity. The influence the density variation of the inhomogeneity on the DSCF is discussed at the same time.

Enhanced Stable and High Voltage of Li/SOCl2 Battery Catalyzed by FePc Particulates Fixed on Activated Carbon Substrates

Efficient catalysts for the reduction reaction of SOCl2 are desired for lithium/thionyl chloride batteries with high and stable voltage. In this work, iron phthalocyanine particulates fixed on activated carbon substrates (FePc/AC) are synthesized by an in situ solid approach under the temperatures lower than 300 °C. U–T curves, the value distance to the average U, dU/dT via mathematical differentiation and numerical analysis were employed to investigate to the catalytic reduction of SOCl2 systematically. The U–T curve of the battery containing the FePc/AC displays almost perfect rectangle profile. The average voltage of the battery contains the FePc/AC is 3.00 V, 0.21 V higher than that without the catalysts. After discharge, the surface of the carbon cathode containing FePc/AC displays a well-constructed loose morphology composed of LiCl nanoparticles around 100 nm in diameter. The inside of carbon cathode shows a dense morphology with a mount of nano holes around 50 nm, indicating that the formed LiCl permeates into the interior of the carbon cathode, attributing to that the FePc/AC nanocomposite catalysts facilitate the reduction of SOCl2, leading the formation loose LiCl film in nano scale for electrolyte SOCl2 and the formed LiCl diffusion.

In vivo liquid biopsy for glioblastoma malignancy by the AFM and LSPR based sensing of exosomal CD44 and CD133 in a mouse model

Glioblastoma (GBM) is the fatal brain tumor in which secreted lactate enhances the expression of cluster of differentiation 44 (CD44) and the release of exosomes, cell-derived nanovesicles (30–200 nm), and therefore promotes tumor malignant progression. This study found that lactate-driven upregulated CD44 in malignant Glioblastoma cells (GMs) enhanced the release of CD44-enriched exosomes which increased GMs' migration and endothelial cells’ tube formation, and CD44 in the secreted exosomes was sensitively detected by “capture and sensing” Titanium Nitride (TiN) - Nanoholes (NH) - discs immunocapture (TIC) - atomic force microscopy (AFM) and ultrasensitive TiN–NH-localized surface plasmon resonance (LSPR) biosensors. The limit of detection for exosomal CD44 with TIC-AFM- and TiN–NH-LSPR-biosensors was 5.29 × 10-1 μg/ml and 3.46 × 10-3 μg/ml in exosome concentration, respectively. Importantly, this work first found that label-free sensitive TiN–NH-LSPR biosensor could detect and quantify enhanced CD44 and CD133 levels in immunocaptured GMs-derived exosomes in the blood and the cerebrospinal fluid of a mouse model of GBM, supporting its potential application in a minimally invasive molecular diagnostic for GBM progression as liquid biopsy.

A Weakly-Coupled Few-Mode Optical Fiber With a Graded Concave High-Index-Ring

This paper proposes a novel refractive index profile design based on few-mode fibers (FMFs) which can support 4 linear polarization (LP) modes. We first present a FMF whose core is dually assisted by a nano-hole (NH) and a high-index-ring (HIR), and then substitute the dual assistance by an innovative graded concave HIR (GC-HIR) assisted structure. Using the finite element method (FEM), the parameters of the NH-HIR and GC-HIR optical fiber are adjusted to investigate their respective minimum effective refractive index difference (minΔn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> ), which is 2.012 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> for the former, and 2.532 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> for the latter. Both optical fibers have a significant improvement on the crosstalk suppression effect, and the GC-HIR optical fiber is even better. The proposed GC-HIR FMF with special refractive index profile has potential application prospects in mode division multiplexing (MDM) optical fiber communication system, and can provide theoretical foundation for the design and analysis of subsequent optical fibers and key components.

The effect of nanorod position on the plasmonic properties of the complex nanorod in nanohole arrays

By moving the nanorod (NR) from the middle toward the rim of the nanohole (NH), i.e. breaking the geometric symmetry, the extraordinary optical transmission (EOT) caused by the dipole coupling of the localized surface plasmon resonance of the NR and the NH can be tuned to redshift exponentially while maintaining the high transmission and overall dimension of the structural unit. This resonant wavelength shift depends strongly on the moving direction of the NR, i.e. whether it is along the long axis or short axis of the rod. Connecting the NR to the NH and increasing the lattice period can significantly redshift the EOT mode, allowing ultra-high transmission in the mid-infrared (MIR) region. The high local E-fields, enhanced propagating waves with a tunable visible-MIR resonance wavelength, make this structure suitable for the design of compact and integrated optical devices from the visible to the MIR wavelength range. In addition, Fano resonances are emerging due to the coupling and hybridization of different plasmonic modes, making the structure beneficial for high sensitivity measurement.