Search

[Display omitted] Hypothesis: Synthetic micro/nanomotors are gaining extensive attention for various biomedical applications (especially in drug delivery) due to their ability to mimic the motion of biological micro/nanoscale swimmers. The feasibility of these applications relies on tight control of propulsion speed, direction, and type of motion (translation, circular, etc.) along with the exerted self-propulsive force. We propose to exploit the variation of both self-propulsion speed and force of active colloids with different patch coverages (with and without supporting layer) for engineering diffusiophoretic micro/nanomotors. Experiments: The microswimmers were designed at various patch coverages (10°, 30°, and 90°) with (Ti/Pt) and without (Pt) an adhesion layer for the catalytic patch through glancing angle metal deposition (GLAD) technique. Mean-square displacement (MSD) analysis was performed to obtain the self-propulsion parameters like speed and angular speed. Using optical tweezers (OT), the self-propulsive force was measured from the force power spectral density. Findings: The findings of our experiments suggest the non-requirement of any adhesion layer preceding the catalyst deposition since the Pt 10° colloidal batch had the maximal self-propulsion speed (4.61 ± 0.3 μ m / s) and force (345 ± 57 f N) for 5% w/v H 2 O 2 fuel concentration. Moreover, the self-propulsion speed and force decreased with increasing patch size, contrary to theoretical estimates. Also, the self-propulsive force obtained from MSD is 2 to 4 times lower in magnitude than the OT based force values. We believe that the self-propelling motion of the micromotors is possibly hindered due to interactions with the surface of the quartz cuvette during the optical microscopic analysis. Further, the MSD is limited to the self-propulsive motion in two dimensions. On the other hand, OT based force measurement involve trapping the particles in the bulk of the solution entirely avoiding the particle–substrate interactions. Hence, OT based force measurements are better than the propulsion velocity based stokes drag force estimates. We believe that this study can lay the foundation in designing efficient micro/nanomotors for translational biomedical applications. [ABSTRACT FROM AUTHOR]

WO3/SnO2 heterostructure nanowire array was fabricated using the Glancing angle deposition technique (GLAD), which is a growth-controlled and catalytic-free process. Well-aligned, vertical NWs are observed in the field emission scanning electron microscope image. The X-ray diffraction measurement revealed SnO2 amorphous and WO3 crystalline nature. The material exhibits strong absorption in the UV region with a direct bandgap of approximately 3.1 eV and 3.6 eV for WO3 and SnO2, respectively. Electrical analysis at room temperature, conducted over a voltage range of -5 to 5 V, demonstrates the device's performance, with a good detectivity (D*) of 6.93 × 1013 and responsivity of 5.9 A/W. Additionally, the device shows a stable switching response at -3 V, with a rise time of 0.30 s and a fall time of 0.32 s. [ABSTRACT FROM AUTHOR]

Copper iodide (CuI) is recognized as a promising p-type transparent material with excellent thermoelectric properties. CuI thin films are typically produced by depositing a copper layer, followed by iodination. However, this process poses challenges in controlling the film's structure, often leading to excessive grain growth in CuI and reduced optical clarity due to increased light scattering from larger grains. In our study, we introduce an innovative method to regulate the structural characteristics of CuI films by employing the glancing angle deposition (GLAD) technique in depositing the initial copper layer. This method creates nanostructured copper films that guide the formation of CuI grains during vapor iodination. By varying the deposition angle and iodination time, we adjust the size and shape of the synthesized CuI nanostructure-sized grains. This directly enhances the thermoelectric properties and the transmittance of the CuI films. We observe that our CuI films result in a 43% increase in Seebeck coefficient (S) of 352 μV/K, leading to a 90% enhancement at room temperature with a power factor of 339 μW/mK2 compared to the previously reported CuI prepared by the vapor iodination method. Additionally, these nanostructured films exhibit high transparency with a transmittance of 85% at a 560 nm wavelength, demonstrating superior optical properties at this wavelength. These results highlight the potential for integrating nanostructured p-type transparent materials into smart windows and cooling systems for optical chips. [ABSTRACT FROM AUTHOR]

Indium oxide (In2O3) is widely accepted as a photocatalyst for its unique optical and electrical properties, as well as its favorable chemical stability. This study investigated the impact of annealing conditions and morphology on photocatalytic properties, by preparing four different nanostructures of In2O3 using glancing angle deposition based on electron beam evaporation. The results indicated that In2O3 annealed at 500 °C for 4 h exhibited optimal crystallization quality and photocatalytic performance. Given the fabricated structures, the slant nanorods structure of In2O3 demonstrated superior photocatalytic performance, achieving a photocurrent density of 0.34 mA/cm2, which was 2.1 times higher than that of the nanofilms (0.16 mA/cm2). Furthermore, this particular structure showed enhanced photodegradation efficiency for Rhodamine B with a degradation rate of 45.69%, suggesting an improvement of about 27% compared to nanofilms. The analysis of Nyquist plots revealed that the slant nanorod structure facilitated enhanced charge transfer capability, thereby significantly improved the photoelectrochemical properties. [ABSTRACT FROM AUTHOR]

Indium oxide (In2O3) is widely accepted as a photocatalyst for its unique optical and electrical properties, as well as its favorable chemical stability. This study investigated the impact of annealing conditions and morphology on photocatalytic properties, by preparing four different nanostructures of In2O3 using glancing angle deposition based on electron beam evaporation. The results indicated that In2O3 annealed at 500 °C for 4 h exhibited optimal crystallization quality and photocatalytic performance. Given the fabricated structures, the slant nanorods structure of In2O3 demonstrated superior photocatalytic performance, achieving a photocurrent density of 0.34 mA/cm2, which was 2.1 times higher than that of the nanofilms (0.16 mA/cm2). Furthermore, this particular structure showed enhanced photodegradation efficiency for Rhodamine B with a degradation rate of 45.69%, suggesting an improvement of about 27% compared to nanofilms. The analysis of Nyquist plots revealed that the slant nanorod structure facilitated enhanced charge transfer capability, thereby significantly improved the photoelectrochemical properties. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) are among the most widely studied thin-film solar cells because of their cost-effectiveness, low toxicity, and simple fabrication method. However, there is still much scope for replacing current DSSC materials due to their high cost, low volume, and lack of long-term stability. Accordingly, indium tin oxide (ITO)-nanorod films were fabricated by electron (E)-beam evaporation using the glancing angle deposition method in this study. Then, the ITO-nanorod was treated with oxygen plasma via a bias-magnetron radio-frequency (RF) sputtering process to improve the efficiency of DSSCs under a varying gas flow rate of 20, 40, 60, 80, and 100 sccm. The field emission scanning electron microscopy (FE-SEM) investigation of the ITO film structure revealed that the obtained nanorod structures have slightly different diameters. At the same time, an increase in the oxygen flow rate resulted in a rougher film surface structure. In this, the lower sheet resistance was received because of rougher morphology. When comparing the DSSCs efficiency (η) test results, we found that at a gas flow rate of 100 sccm, the highest efficiency value showed 9.5%. On the other hand, the ITO-nanorod without plasma treatment exhibited the lowest η. Hence, plasma technology can be practically applied to improve the η of DSSC devices. This study will be a prototype of a highly advanced solar cell manufacturing method for the solar cell industry. [ABSTRACT FROM AUTHOR]

In this study, we explore the practical application of Cu2O nanorod (NR) in photodetection application which is fabricated on Si substrate using e-beam evaporation with an integrated glancing angle deposition (GLAD) technique. Notably, this fabrication method does not rely on catalysts. X-ray diffraction (XRD) analysis reveals two distinct peaks at ~ 36.98° and ~ 43.60°, corresponding to (111) and (200) crystal orientations with an average crystallite size ~ 13.01 nm. This confirms the presence of cuprous oxide (Cu2O) and thus exhibiting a polycrystalline structure. FE-SEM image examination also confirms the growth of Cu2O-NRs, displaying a well-aligned structure with average diameter of ~ 30 nm and total length of ~ 250 nm. At a fixed voltage of + 1.5 V, the device remarkably displays a constant switching response when light intensity increases from ~ 0.86 mW/cm2 to ~ 2.59 mW/cm2. The photodetector records a fall time of rise time of ~ 0.153 s and a fall time of ~ 0.164 s. The device exhibits responsivity in the visible and near-infrared spectrums with its maximum peak intensity observed at ~ 750 nm and a responsivity of ~ 0.9 A/W. Furthermore, the device demonstrates a low noise equivalent power of ~ 8.52 × 10− 13 W and a detectivity value of ~ 3.29 × 1012 Jones. The electrical analysis demonstrates a promising photosensitivity characteristic of the Cu2O-NR device which may be applicable in various optoelectronics applications. [ABSTRACT FROM AUTHOR]

Porous copper films used in current collectors have been shown to improve the stability of Li-ion batteries. They can be applied in Si-based photodiodes, sensors or as microradiators. Their fabrication, however, remains a challenge. In this work, we report on the direct deposition of porous copper films using magnetron sputtering in regular chamber geometry. We show how by using appropriate process gases and substrate temperatures, it is possible to control the morphology of the deposited films. In particular, the optimization of the argon to oxygen flow ratios and flow values leads to small porosification of the deposited copper films. Further, heating the substrate during deposition enables the growth of pore sizes into mesoporous and macroporous ranges. This approach is scalable, and since it does not require glancing angle deposition enables the easy coverage of large surfaces with uniformly porous films. [ABSTRACT FROM AUTHOR]

Nanostructures represent a frontier where meticulous attention to the control and assessment of structural dimensions becomes a linchpin for their seamless integration into diverse technological applications. However, determining the critical dimensions and optical properties of nanostructures with precision still remains a challenging task. In this study, by using an integrative and comprehensive methodical series of studies, the evolution of the depolarization factors in the anisotropic Bruggeman effective medium approximation (AB‐EMA) is investigated. It is found that these anisotropic factors are extremely sensitive to the changes in critical dimensions of the nanostructure platforms. In order to perform a systematic characterization of these parameters, spatially coherent, highly‐ordered slanted nanocolumns are fabricated from zirconia, silicon, titanium, and permalloy on silicon substrates with varying column lengths using glancing angle deposition (GLAD). In tandem, broad‐spectral range Mueller matrix spectroscopic ellipsometry data, spanning from the near‐infrared to the vacuum UV (0.72–6.5 eV), is analyzed with a best‐match model approach based on the anisotropic Bruggeman effective medium theory. The anisotropic optical properties, including complex dielectric function, birefringence, and dichroism, are thereby extracted. Most notably, the research unveils a generalized, material‐independent inverse relationship between depolarization factors and column length. It is envisioned that the presented scaling rules will permit accurate prediction of optical properties of nanocolumnar thin films improving their integration and optimization for optoelectronic and photonic device applications. As an outlook, the highly porous nature and extreme birefringence properties of the fabricated columnar metamaterial platforms are further explored in the detection of nanoparticles from the cross‐polarized integrated spectral color variations. [ABSTRACT FROM AUTHOR]

Ga₂O₃ nanowire arrays were fabricated on silicon substrates using a combination of e-beam evaporation and glancing angle deposition (GLAD). Microscopic imaging and energy dispersive X-ray (EDX) mapping confirmed the formation of nanowire-like structures with precise stoichiometry. X-ray diffraction verified the crystalline β-Ga2O3 structure. Optical bandgap values of 3.2 eV and 4.5 eV were determined through UV–Vis absorption spectroscopy utilizing Tauc's plot. The optoelectronic properties of an Au/Ga2O3 nanowire/p-Si/In device were assessed via current-voltage (I-V) measurements, with a free carrier concentration (Nd) of 5.6 × 1017 cm− 3 obtained from capacitance-voltage (C-V) measurements. Temperature-dependent I-V characteristics revealed a decrease in Ideality factor and series resistance with increasing temperature, along with an increase in barrier height, indicating barrier inhomogeneities. Wavelength-dependent responsivity and detectivity measurements demonstrated enhanced performance in the UV (~ 300 nm) and near-UV (~ 400 nm) regions. In the UV region, the device exhibited responsivity values of 2.29 A/W and 6.54 A/W, and detectivity values of 2.51 × 109 Jones and 8.64 × 109 Jones, respectively. Highlights: Ga2O3 nanowire arrays were successfully fabricated using a combination of e-beam evaporation and glancing angle deposition (GLAD) on silicon substrates. Optical bandgap values of 3.2 eV and 4.5 eV were determined, highlighting the material's suitability for optoelectronic applications. Capacitance-Voltage (C-V) measurements revealed a free carrier concentration (Nd) of 5.6 × 1017 cm−3, offering valuable insights into the electrical properties of the material. Temperature-dependent I-V characteristics indicated the presence of barrier inhomogeneities, suggesting complex electrical behaviour. Enhanced device performance was demonstrated through wavelength-dependent responsivity and detectivity measurements, with R = 2.29 A/W & 6.54 A/W and D* = 2.51 × 109 Jones & 8.64 × 109 Jones, respectively, in the UV (~ 300 nm) and near-UV (~ 400 nm) regions. The Ga2O3-based device exhibited significant potential as a detector or sensor, especially for deep UV and near-UV wavelengths. [ABSTRACT FROM AUTHOR]

In this work, Ag nanoparticle-decorated TiO2 nanowire (ADT) photoanodes were prepared by varying the speed of the substrate rotation using the Glancing Angle Deposition Technique (GLAD) for Dye-Sensitized Solar Cell (DSSC) applications. The High Resolution-Transmission Electron Microscopy analysis reveals the presence of TiO2 and Ag crystals, which is also confirmed by the Selected Area Electron Diffraction and XRD results. The optical absorption spectrum of the ADT photoanode sample deposited at 30 Revolutions per Minute (rpm) of GLAD rotation shows enhancement in the UV and visible regions as compared to other photoanode samples. It is also observed from the Tauc plot analysis that the band gap of TiO2 nanowire decreases after the incorporation of Ag nanoparticles, as well as when the speed of substrate rotation increases. Finally, the performance of the fabricated DSSCs based on bare TiO2-NW and ADT photoanodes deposited at different GLAD rpms was compared. It is interesting to observe that by increasing the speed of GLAD rpm, the efficiency of DSSC based on ADT deposited at 30 rpm (ADT@30 rpm) is enhanced by ~ 18.72% compared to ADT deposited at 15 rpm (ADT@15 rpm) based DSSC. The best result was achieved from DSSC based on ADT@30 rpm photoanode, which gives the maximum efficiency of ~ 2.79%, with corresponding open-circuit voltage (VOC) and short-circuit current (JSC) values of ~ 0.57 V and ~ 14.81 mA/cm2, respectively. Therefore, the proposed method of developing photoanodes using this simple GLAD technique may be applicable for developing efficient DSSC and other optoelectronic applications. [ABSTRACT FROM AUTHOR]

This work describes the fabrication and characterization of a new high surface area nanocomposite electrode containing reduced graphene oxide (rGO) and titanium nitride (TiN) for electrochemical applications. This approach involves electrochemically depositing rGO on a high surface area TiN nanorod array electrode to form a new nanocomposite electrode. The TiN nanorod array was first formed by the glancing angle deposition technique in a DC (Direct Current) sputtering system. GO flakes of ~1.5 μm in diameter, as confirmed by Dynamic Light Scattering (DLS), were electrodeposited on the nanostructured TiN electrode via the application of a fixed potential for one hour. The surface morphology of the as-prepared rGO/TiN electrode was evaluated by scanning electron microscopy (SEM) and the presence of rGO on TiN was confirmed by Raman Microscopy. The CV shows an increase in the capacitive current at rGO/TiN as compared to TiN. The rGO decorated TiN electrode was then used for analyzing the electrocatalytic oxidation of ascorbic acid and dopamine, and the reduction of nitrate by CV and linear sweep voltammetry (LSV), respectively. CV or LSV show that the electrochemical kinetics of these three analytes are significantly faster on rGO/TiN than TiN itself. Overall, the rGO/TiN electrode showed better electrochemical behavior for biomolecules like ascorbic acid and dopamine as well as another target analyte, nitrate ions, compared to TiN by itself. [ABSTRACT FROM AUTHOR]

Ag nanoparticles (NPs) were decorated on the surface of axial n-ZnO/p-CuO heterostructure (HS) nanowires (NWs) by using a catalytic-free and well-controlled technique called glancing angle deposition (GLAD). A typical high-resolution transmission electron microscope (HR-TEM) image shows formation of an Ag NPs on the surface of axial HS NW consisting of ZnO NW at the top and CuO NW at the bottom. Moreover, the photodetector (PD) based on Ag (NPs)-ZnO/CuO HS NW sample showed a high responsivity ( R λ ) of ~ 118 A/W, specific detectivity ( D ∗ ) of ∼ 1.38 × 10 12 Jones and noise equivalent power (NEP) as low as ∼ 2.42 × 10 - 12 W under 365 nm UV illumination. Further, the device showed a low dark current of ~ 5.25 nA at − 1 V applied bias with fast device response of ~ 0.072 s and ~ 1.73 s for rise and fall times respectively. Thus, the fabricated Ag (NPs)-ZnO/CuO HS NWs device can be a suitable applicant for UV photodetector application. [ABSTRACT FROM AUTHOR]

The document "Thin-Film Deposition: From Fundamental Research to Applications" published in the journal Micromachines highlights the advancements in technology driven by thin-film deposition techniques. The special issue focuses on various research contributions, including studies on tungsten thin films for microheating applications, samarium-doped BiFeO3 films, TiO2 bilayers for electron transport layers, Mn3[Fe(CN)6]2·nH2O nanosheets for ion batteries, and more. These studies explore the properties and applications of thin films in fields such as electronics, energy storage, and biomedicine, showcasing the diverse potential of thin-film technology. [Extracted from the article]

Here, glancing angle deposition is employed to synthesize the undoped GeO2 and Mg-doped (0.4 and 0.8 at. %) GeO2 nanowires (NWs) on a Si substrate. The microscopic images show the formation of the NW-like morphology of the grown materials. The gradual decrease in the average ratio of length to diameter depicts the worsening of the formation of NWs with the incorporation of Mg into the GeO2 host lattice. This also affects the crystallinity characteristics of the materials, which have been demonstrated from the selected area electron diffraction (SAED) pattern of the materials. The polycrystallinity nature of undoped GeO2 NWs changes to amorphous due to the introduction of Mg, which has been confirmed from both the obtained SAED and x-ray diffraction patterns of the samples. The presence of Mg was confirmed from the obtained broad bands at 473 and 437 cm−1 in the Fourier transmission spectrum of the doped samples. The increasing conductance with the temperature of Au/undoped GeO2 devices can be explained by the thermionic emission process, whereas the Mg-GeO2 device shows an overall decrease in conductance with increasing temperature. We have ascribed the origin of this abnormal conductance as the positive temperature coefficient of resistance, which is one of the first reports, due to the generation of random grain boundaries and enormous electron trapping at the Au/Mg-GeO2 NW junction. Furthermore, the undoped GeO2 NW device shows good temperature-dependent conductivity as well as stability compared to the doped one. [ABSTRACT FROM AUTHOR]

The recent era of research has been focused on attaining precise and adjustable propulsion modes in micromotors, with remarkable implications in microrobotics and active‐matter applications. This study introduces a novel design of rod‐shaped micromotors featuring light‐driven motion and wavelength‐dependent multimodal swimming behavior. The micromotors are fabricated through the Glancing Angle Deposition (GLAD) technique, which offers a flexible approach to engineering surfaces by incorporating photocatalytic materials (TiO2 and Cu2O) at specific locations. Here, three distinct designs of micromotors (titania, hybrid‐1, and hybrid‐2) are presented that are programmed to showcase diverse behaviors of movements (linear, helical, and axial rotation) when exposed to a specific wavelength. The application of light facilitates convenient control over activity and mode switching by altering between UV and visible ranges. Numerical modeling using a finite element approach is performed to validate the experimental results, demonstrating excellent agreement with the experimental findings. The present study is anticipated to be helpful in tailoring such complex micro/nanoscale advanced functional materials with intricating swimming modes desired for various applications in micro/nanorobotics. [ABSTRACT FROM AUTHOR]

UV-nanoimprint lithography (UV-NIL) has been proved to be an efficient method for preparing nanodrug delivery systems. Herein, we used UV-NIL associated with the glancing angle deposition (GLAD) process of electron beam evaporation to prepare Au-coated PLGA nanocylinders loaded with PTX (PTX-PLGA-Au NCs) to enhance anticancer efficacy by the cooperative treatment of photothermal-chemotherapy. PTX-PLGA-Au NCs with different length-to-diameter ratios can be prepared by controlling the concentration of PLGA and regulating the angle of GLAD. Upon 808 nm near-infrared (NIR) irradiation, PTX-PLGA-Au NCs exhibit a stable and repeatable photothermal effect. Besides, hyperthermia generated by the Au layer on the surface of PTX-PLGA-Au NCs under laser irradiation promoted the rapid release of PTX. The in vitro studies demonstrated that PTX-PLGA-Au NCs can achieve the synergistic effect of photothermal-chemotherapy, leading to increased cell cytotoxicity. Therefore, UV-NIL combined with the GLAD process produced a promising nanofabrication method for efficiently developing a multifunctional nanoplatform for cancer treatment. [ABSTRACT FROM AUTHOR]

This study presents an integrated approach combining surface‐enhanced Raman spectroscopy (SERS) with a specialized deep learning algorithm, SFNet, to offer a rapid, accurate, and label‐free alternative for COVID‐19 diagnosis and viral load quantification. The SiO2‐coated silver nanorod arrays are employed as the SERS substrates, fabricated using a reliable and effective glancing angle deposition technique. A dataset of 4800 SERS spectra from 120 positive and 120 negative inactivated clinical human nasopharyngeal swabs are collected directly on the SERS substrates without any labels. A SFNet algorithm is tailored to adapt to the unique spectral features inherent to SERS data, achieving a test accuracy of 98.5% and a blind test accuracy of 99.04%. Moreover, an optimized SFNet algorithm unveils the capability of estimating SARS‐CoV‐2 viral loads, accurately predicting the cycle threshold values (Ct values) of the three vital gene fragments with a root mean square error (RMSE) of 1.627 (1.3 for blind test). The methodology is substantiated using actual clinical specimens and completed in <15 min, thereby strengthening its real‐world point‐of‐care applicability. This rapid and precise yet label‐free modality competes favorably with classical reverse‐transcription real‐time polymerase chain reaction (RT‐PCR) and marks an advancement in SERS‐based sensor algorithms. [ABSTRACT FROM AUTHOR]

In this work, we synthesized the TiO2 nanowire (NW) and Gold (Au) nanoparticle (NP) aligned TiO2-NW using glancing angle deposition (GLAD) associated with e-beam evaporation technique. Further, synthesized samples annealed at 400 °C, 600 °C, and 900 °C to change crystallite nature of material. The presence of anatase phase has more percentage than rutile phase till 600 °C, while annealed at 900 °C most of phase transformed into rutile phase. XRD and Raman's spectra verified the annealing temperature phase transition. The effect of surface plasmon resonance (SPR) of Au-NP was observed in optical absorption and photoluminescence (PL) spectra. Moreover, anatase-rutile phase exhibited enhanced optical absorption. The bandgap decreases and crystallite size increases while increasing value of annealing temperature. The field emission scanning electron microscope (FESEM) images confirm the formation of TiO2-NW along with Au-NP on Si substrate. The average length and diameter of TiO2-NW were ⁓230 nm and ⁓54 nm, respectively. It was noted that the diameter of the Au-NPs varied, ranging from ⁓5 nm to ⁓10 nm. This phase transformation investigation will ultimately aid in the optimization of synthesis processes in numerous photo activity related applications. The common potential applications are photocatalysis, gas sensors, photovoltaics, memory and biomedical applications. [ABSTRACT FROM AUTHOR]

We report the growth of columnar structures of orthorhombic AgTe by radio-frequency (RF) magnetron sputtering at room temperature. The structures were formed spontaneously by direct deposition of Te on Ag nanoparticles prepared by glancing angle deposition without exposure to air. Anomalous diffusion of Ag nanoparticles into the deposited Te led to the formation of columnar AgTe. The gaps in the columnar structure were filled with Te, which can be removed by sublimation. This is the first report on the preparation of orthorhombic AgTe by vapor deposition. The formation of columnar orthorhombic AgTe is attributed to the small grain size of the Ag nanoparticles, which prevents crystal nucleation of the stable Ag2Te phase, and the non-oxidized Ag-Te direct interface, which induces fast anomalous diffusion and a strong electrochemical reaction. [ABSTRACT FROM AUTHOR]

The inherently weak chiroptical responses of natural materials limit their usage for controlling and enhancing chiral light-matter interactions. Recently, several nanostructures with subwavelength scale dimensions were demonstrated, mainly due to the advent of nanofabrication technologies, as a potential alternative to efficiently enhance chirality. However, the intrinsic lossy nature of metals and the inherent narrowband response of dielectric planar thin films or metasurface structures pose severe limitations toward the practical realization of broadband and tailorable chiral systems. Here, we tackle these problems by designing all-dielectric silicon-based L-shaped optical metamaterials based on tilted nanopillars that exhibit broadband and enhanced chiroptical response in transmission operation. We use an emerging bottom-up fabrication approach, named glancing angle deposition, to assemble these dielectric metamaterials on a wafer scale. The reported strong chirality and optical anisotropic properties are controllable in terms of both amplitude and operating frequency by simply varying the shape and dimensions of the nanopillars. The presented nanostructures can be used in a plethora of emerging nanophotonic applications, such as chiral sensors, polarization filters, and spin-locked nanowaveguides. L-shaped silicon metamaterials are realized exhibiting broadband and enhanced chirality. The current work sets new benchmarks in the assembly of ultrathin dielectric chiral metamaterials that can efficiently control chiral light-matter interactions. [ABSTRACT FROM AUTHOR]

In this paper, nanostructured tungsten oxide (WO3) thin films are deposited using the RF-magnetron sputtering technique in Glancing Angle (GLAD) arrangement. Variation in the structural, morphological, optical, and resistive switching (RS) characteristics of nanostructured WO3 film is investigated as a function of GLAD angle (60°–80°). Electrical studies on nanostructured WO3 films deposited at room temperature are found to exhibit enhanced bipolar resistive-switching properties in metal–insulator–metal pattern [Au/WO3/ITO]. The RON/ROFF ratio between high and low resistance states was noted to be about 190 besides a minimum set voltage of ∼2.22 V in the case of the WO3 thin film deposited at the 70° glancing angle. A detailed current transport mechanism analysis indicates the existence of ohmic-behavior and trap-assisted space charge limited conduction as the governing mechanisms at the state of low and high applied bias, respectively. Good data-retention characteristics coupled with reproducible and fast RS capabilities obtained with Au/WO3/ITO device structure promise scope of rapid development in future RS-based novel memory device applications. [ABSTRACT FROM AUTHOR]

Nano/micromotors (NMs) are tiny structures capable of converting various forms of energy into mechanical motion at the micro and nanoscale. These motors operate in environments characterized by low inertia and low Reynolds numbers. The potential applications of NMs are vast, particularly in the fields of biomedicine and environmental science. One of the most intriguing developments in this field is the integration of NMs with surface-enhanced Raman scattering (SERS) spectroscopy. SERS is a powerful analytical technique that enhances the Raman intensity of molecules, allowing for highly sensitive detection and analysis of trace amounts of substances. This integration offers highly precise and localized ultrasensing capabilities. The combination of NMs with SERS can also facilitate real-time imaging inside living organisms. This has immense potential in chemical and cell biology and medical diagnostics and prognosis. Herein this review describes the types of NMs and their fabrication, the incorporation of plasmonic nanostructures, capable of creating strong electromagnetic fields when illuminated by light, which in turn enhances the Raman signals significantly, their applications, and their future prospects in areas such as precision medicine, environmental monitoring, and possibly even in new realms like microscale robotics and targeted therapeutics. [ABSTRACT FROM AUTHOR]

Magnetically actuated microrobots have become a research hotspot in recent years due to their tiny size, untethered control, and rapid response capability. Moreover, an increasing number of researchers are applying them for micro-/nano-manipulation in the biomedical field. This survey provides a comprehensive overview of the recent developments in magnetic microrobots, focusing on materials, propulsion mechanisms, design strategies, fabrication techniques, and diverse micro-/nano-manipulation applications. The exploration of magnetic materials, biosafety considerations, and propulsion methods serves as a foundation for the diverse designs discussed in this review. The paper delves into the design categories, encompassing helical, surface, ciliary, scaffold, and biohybrid microrobots, with each demonstrating unique capabilities. Furthermore, various fabrication techniques, including direct laser writing, glancing angle deposition, biotemplating synthesis, template-assisted electrochemical deposition, and magnetic self-assembly, are examined owing to their contributions to the realization of magnetic microrobots. The potential impact of magnetic microrobots across multidisciplinary domains is presented through various application areas, such as drug delivery, minimally invasive surgery, cell manipulation, and environmental remediation. This review highlights a comprehensive summary of the current challenges, hurdles to overcome, and future directions in magnetic microrobot research across different fields. [ABSTRACT FROM AUTHOR]

Efficient photocatalytic performance plays a pivotal role in tackling our present energy challenges. A well-designed arrangement of nanoscale semiconductors and metallic components within multi-heterojunction photocatalysts can establish rapid transport pathways, enhancing the separation and migration of charge carriers. This approach offers a viable strategy towards achieving optimal photocatalytic efficiency. Herein, the glancing angle deposition technique (GLAD) technology of electron beam evaporation and spin-coating method were used to construct Fe2O3/TiO2/WO3/Ti3C2Tx quaternary composite materials with serial heterojunctions. Photocatalytic activity was assessed through photoelectrochemical tests, revealing that the Fe2O3/TiO2/WO3/Ti3C2Tx composite material outperformed its counterparts under visible-light irradiation. Notably, it achieved the highest photocurrent response, with a maximum photocurrent density of 1.09 mA/cm2. This represented a substantial improvement, surpassing Fe2O3, Fe2O3/TiO2, and Fe2O3/TiO2/WO3 photocatalysts by factors of 36, 2.8 and 1.25, respectively. This remarkable enhancement can be attributed to the formation of three heterojunctions in series, creating multiple pathways for efficient charge transfer and separation during the photocatalytic process. Furthermore, we proposed a photocatalytic mechanism for quaternary heterojunctions based on band structure analysis. [ABSTRACT FROM AUTHOR]

The present study investigates the synthesis of vertically aligned MnO2 nanowires (NW) decorated with gold (Au) and silver (Ag) nanoparticles (NP) via the glancing angle deposition (GLAD) technique without a need for a catalyst. The cross-sectional field emission scanning electron microscopy (FESEM) image and energy-dispersive X-ray spectroscopy (EDS) confirm the successful adornment of Ag NP and Au NP on the top surface of MnO2 NW. Elemental mapping has verified the presence of manganese (Mn), oxygen (O), silicon (Si), Ag, and Au within the sample. X-ray diffraction (XRD) patterns reveal the polycrystalline growth of the MnO2 film with the preferred orientation. AFM reveals that the surface roughness of Au NP/MnO2 NW is more than Ag NP/MnO2 NW. The measured water contact angles of Au NP/MnO2 NW, Ag NP/MnO2 NW, and MnO2 NW were 125° and 113°, respectively. Ag NP/MnO2 NW showed more hydrophilic properties under UV illumination than Au NP/MnO2 NW owing to the efficient separation of photogenerated electron–hole pairs. Ag NP/MnO2 NW's higher photocatalytic activity than Au NP/MnO2 NW is attributed to the increased light absorption of the Ag NP in the UV region. The overall enhancement after decorating the noble metal NP on MnO2 NW could open new avenues for self-cleaning applications. [ABSTRACT FROM AUTHOR]

Slanted gratings, commonly used for manipulating light in various applications, are typically fabricated using conventional top-down methods. However, these methods have limitations on material choice. This paper explores the use of glancing angle deposition (GLAD) to fabricate slanted gratings with various materials and slant angles on silicon (Si) and quartz (SiO2) substrates. The process involves the first step of creating a template using electron beam lithography, lift-off, and dry etching, and the second step of electron beam evaporation at a glancing angle on the prefabricated template. The template consists of grating structures with very shallow trenches. Different materials, such as chromium (Cr), copper (Cu), aluminum oxide (Al2O3), and titanium oxide (TiO2), were used in the GLAD process to create slanted grating structures on Si or SiO2 substrates, showcasing their versatility. Here, the formation of the slanted grating is due to the shadowing effect that leads to deposition onto the protruded grating lines but not into the trench. Using TiO2 as the source material, the GLAD technique can produce slanted gratings with various angles by adjusting the deposition angle. The optical characteristics of the slanted grating prepared using GLAD were verified through simulations with COMSOL software, confirming its excellent light guide performance. [ABSTRACT FROM AUTHOR]

An Aluminum Oxide (Al2O3) nanorod (NR) array–based device has been synthesized upon an Al2O3 thin film (TF) by electron beam (E-beam) evaporation with a glancing angle deposition technique. The complete fabrication has been done inside a vacuum coating unit. The Al2O3 nanostructures have been fabricated on a silicon substrate. Field emission scanning electron microscopy and transmission electron microscopy show a vertically aligned Al2O3 NR array. From the Tauc plot, the optical band energies are estimated as 5 eV and 5.5 eV for the bare Al2O3 TF and Al2O3 NR/Al2O3 TF devices, respectively. Significant improvement has been observed in photosensitivity by 10 fold, detectivity by 4.2 fold, and noise equivalent power (NEP) by 16.5 fold for the Al2O3 NR/Al2O3 TF device compared with the Al2O3 TF. The Al2O3 NR/Al2O3 TF device exhibits a very fast photoswitching response (rise time = 0.15 s and fall time = 0.13 s). Therefore, the Al2O3 NR/Al2O3 TF device proves to be a prominent candidate for next-generation optoelectronic device applications. [ABSTRACT FROM AUTHOR]

In this work, we report magnetic and optical anisotropies in tilted nickel (Ni) nanocolumns and their dependencies on the film growth conditions. The Ni nanocolumns were prepared using electron beam evaporation technique in conjunction with glancing angle deposition methodology. The film depositions were performed at various in-situ substrate temperatures viz. 30 °C, 150 °C, 250 °C and 300 °C. An increase in material density with in-situ substrate temperature due to the thermal diffusion mediated coalescence of neighbouring grains was observed. The results were further corroborated with the alterations in surface morphology of the films. The modification in tilt angle of the Ni nanocolumns was also observed with in-situ substrate heating due to the non-ballistic growth approach. The presence of uniaxial optical anisotropy was established in the films deposited at low substrate temperatures (< 250 °C) using generalized ellipsometry (GE). However, the uniaxial optical anisotropy was found to be negligible for the high temperature deposited films due to thermal diffusion effect. SQUID measurements were performed for quantification of magnetic anisotropy in the films. The estimated magnetic anisotropy energy confirmed low substrate temperature deposited films to be more anisotropic as compared to others. Magnetic coercivity of the films showed film porosity dependent changes in the field values. Overall, the present investigation demonstrates anisotropic behaviour of nanocolumnar nickel thin films for non-ballistic glancing angle deposition. [ABSTRACT FROM AUTHOR]

Aluminum nitride (AlN) is a material of growing interest for power electronics, fabrication of sensors, micro-electromechanical systems, and piezoelectric generators. For the latter, the formation of nanowire arrays or nanostructured films is one of the emerging research directions. In the current work, nanostructured AlN films manufactured with normal and glancing angle magnetron sputter depositions have been investigated with scanning and transmission electron microscopy, X-ray diffraction, atomic force microscopy, and optical spectroscopy. Growth of the nanostructures was realized utilizing metal seed particles (Ag, Au, and Al), allowing the control of the nucleation and following growth of AlN. It was demonstrated how variations of seed particle material and size can be used to tune the parameters of nanostructures and morphology of the AlN films. Using normal angle deposition allowed the growth of bud-shaped structures, which consisted of pillars/lamellae with wurtzite-like crystalline structures. Deposition at a glancing angle of 85° led to a film of individual nanostructures located near each other and tilted at an angle of 33° relative to the surface normal. Such films maintained a high degree of wurtzite-like crystallinity but had a more open structure and higher roughness than the nanostructured films grown at normal incidence deposition. The developed production strategies and recipes for controlling parameters of nanostructured films pave the way for the formation of matrices to be used in piezoelectric applications.

Laser damage resistance of coatings is determined by thin film materials and multilayer designs, all of which limit the overall performance of optical elements and all laser systems. Coatings that consist of high band-gap materials and are capable to withstand extreme laser power under the multiple pulse irradiation, could substantially expand the current capabilities of generated laser power in major laser facilities. In this report all-silica high reflectivity mirrors were coated using GLAD method and have been locally irradiated by the pulsed laser in order to gain close to fundamental laser damage resistivity. Optical elements exceeded the optical resistivity of fused silica substrate and reached 200 J/cm2 in pulsed ns regime at 355 nm wavelength. The achieved major laser damage resistivity improvement of high reflectivity mirrors will have an essential effect in major laser facilities working towards laser fusion.

In this paper, the possibility of preparing silver nanostructures with a high area density of nanoparticles of various shapes by the ion beam sputtering (IBS) method, using a glancing angle deposition (GLAD) configuration, and subsequent irradiation with heavy ions, was tested. In the experiment, keV Ar+ ions were used for both IBS and bombardment. The prepared nanostructures were analyzed by RBS and microscopic methods of SEM and AFM. It turned out that IBS/GLAD makes it possible to create silver nanostructures (networks of individual silver nanoparticles), but only with relatively low areal densities (∼ 70 µm2). The bombardment led to changes in the porosity only after high ion fluences, but also to disruption of the nanostructures. Even so, the IBS method with GLAD configuration has been shown to be a promising way to prepare high-porosity nanostructures. Nevertheless, further experimental efforts will be needed to find the optimal technology. [ABSTRACT FROM AUTHOR]

Sample preparation for mass spectroscopy typically involves several liquid and solid phase clean-ups, extractions, and other unit operations, which are labour-intensive and error-prone. We demonstrate a centrifugal microfluidic platform that automates the whole blood sample's preparation and clean-up by combining traditional liquid-phase and multiple solid-phase extractions for applications in mass spectroscopy (MS)-based small molecule detection. Liquid phase extraction was performed using methanol to precipitate proteins in plasma separated from a blood sample under centrifugal force. The preloaded solid phase composed of C18 beads then removed lipids with a combination of silica particles, which further cleaned up any remaining proteins. We further integrated the application of this sample prep disc with matrix-assisted laser desorption/ionization (MALDI) MS by using glancing angle deposition films, which further cleaned up the processed sample by segregating the electrolyte background from the sample salts. Additionally, hydrophilic interaction liquid chromatography (HILIC) MS was employed for detecting targeted free amino acids. Therefore, several representative ionic metabolites, including several amino acids and organic acids from blood samples, were analysed by both MALDI-MS and HILIC-MS to demonstrate the performance of this sample preparation disc. The fully automated blood sample preparation procedure only took 35 mins, with a throughput of three parallel units. [ABSTRACT FROM AUTHOR]

Aluminum nitride (AlN) is a material of growing interest for power electronics, fabrication of sensors, micro-electromechanical systems, and piezoelectric generators. For the latter, the formation of nanowire arrays or nanostructured films is one of the emerging research directions. In the current work, nanostructured AlN films manufactured with normal and glancing angle magnetron sputter depositions have been investigated with scanning and transmission electron microscopy, X-ray diffraction, atomic force microscopy, and optical spectroscopy. Growth of the nanostructures was realized utilizing metal seed particles (Ag, Au, and Al), allowing the control of the nucleation and following growth of AlN. It was demonstrated how variations of seed particle material and size can be used to tune the parameters of nanostructures and morphology of the AlN films. Using normal angle deposition allowed the growth of bud-shaped structures, which consisted of pillars/lamellae with wurtzite-like crystalline structures. Deposition at a glancing angle of 85° led to a film of individual nanostructures located near each other and tilted at an angle of 33° relative to the surface normal. Such films maintained a high degree of wurtzite-like crystallinity but had a more open structure and higher roughness than the nanostructured films grown at normal incidence deposition. The developed production strategies and recipes for controlling parameters of nanostructured films pave the way for the formation of matrices to be used in piezoelectric applications. [ABSTRACT FROM AUTHOR]

Fano resonance, known for its unique asymmetric line shape, has gained significant attention in photonics, particularly in sensing applications. However, it remains difficult to achieve controllable Fano parameters with a simple geometric structure. Here, a novel approach of using a thin‐film optical Fano resonator with a porous layer to generate entire spectral shapes from quasi‐Lorentzian to Lorentzian to Fano is proposed and experimentally demonstrated. The glancing angle deposition technique is utilized to create a polarization‐dependent Fano resonator. By altering the linear polarization between s‐ and p‐polarization, a switchable Fano device between quasi‐Lorentz state and negative Fano state is demonstrated. This change in spectral shape is advantageous for detecting materials with a low‐refractive index. A bio‐particle sensing experiment is conducted that demonstrates an enhanced signal‐to‐noise ratio and prediction accuracy. Finally, the challenge of optimizing the film‐based Fano resonator due to intricate interplay among numerous parameters, including layer thicknesses, porosity, and materials selection, is addressed. The inverse design tool is developed based on a multilayer perceptron model that allows fast computation for all ranges of Fano parameters. The method provides improved accuracy of the mean validation factor (MVF = 0.07, q‐q') compared to the conventional exhaustive enumeration method (MVF = 0.37). [ABSTRACT FROM AUTHOR]

Photodetectors based on one-dimensional structures have recently attracted great interest due to their high surface-to-volume ratio and light-trapping efficiency. In this study, a self-powered photodetector based on vertically aligned WO3 nanorod with SiO2 as an interfacial layer has been fabricated using glancing angle deposition. Scanning electron microscope (SEM) analysis confirms the successful growth of WO3 nanorod and SiO2 thin film with a thickness of ~125 nm and ~70 nm, respectively. The device's optical properties were also analysed using UV-visible spectroscopy, which revealed a wide bandgap and an intense absorption peak in the ultraviolet region. The electrical analysis showed a nonlinear rectifying current-voltage behaviour with high photosensitivity. Additionally, the photodetector exhibits a fast response of 0.31 s rise time and 0.32 s fall time at 0 V. Moreover, the devices possess a high detectivity and a responsivity of 0.68 mA/W. Thus, the obtained finding reveals a potential candidate for self-powered photodetector application. [ABSTRACT FROM AUTHOR]

Glancing angle deposition (GLAD) of CdTe can produce a cubic, hexagonal, or mixed phase crystal structure depending upon the oblique deposition angles (Φ) and substrate temperature. GLAD CdTe films are prepared at different Φ at room temperature (RT) and a high temperature (HT) of 250 °C and used as interlayers between the n-type hexagonal CdS window layer and the p-type cubic CdTe absorber layer to investigate the role of interfacial tailoring at the CdS/CdTe heterojunction in photovoltaic (PV) device performance. The Φ = 80° RT GLAD CdTe interlayer and CdS both have the hexagonal structure, which reduces lattice mismatch at the CdS/CdTe interface and improves electronic quality at the heterojunction for device performance optimization. The device performance of HT CdS/CdTe solar cells with Φ = 80° RT with 50 to 350 nm thick GLAD CdTe interlayers is evaluated in which a 250 nm interlayer device shows the best device performance with a 0.53 V increase in open-circuit voltage and fill-factor product and a 0.73% increase in absolute efficiency compared to the HT baseline PV device without an interlayer. [ABSTRACT FROM AUTHOR]

Nowadays, most SERS platforms are based on plasmonic metals like silver and gold. The current scientific achievement is to construct SERS non-metallic platform with SERS activity not worse than in case of standard metallic platforms. The prominent combination of opto-electronic properties of TiN (titanium nitride) makes it a promising alternative plasmonic material for noble metals. So far, the TiN nanostructures are widely tested in catalysis, especially in photocatalysis. Despite the TiN potential in SERS sensing applications, there are still several fundamental issues preventing its wide practical application. In this work, the surface morphology of TiN layers was tuned from planar 2D to a high aspect ratio 1D nanorod-like structures by industrially scalable normal and glancing angle deposition (GLAD) pulsed DC reactive sputtering. The morphology of formed samples was studied by SEM microscopy, while the crystallographic properties were examined by Raman and XRD method. The opto-electrical parameters measured by spectroscopic ellipsometry, and DRS spectroscopy revealed substantial changes in optical properties of the TiN films with the variation of glancing angle. This in turn opened the way for tailoring the surface plasmon resonance and hence for SERS activity. [ABSTRACT FROM AUTHOR]

Herein, the impact of postdeposition annealing on resistive switching behavior of radio frequency magnetron sputtered WO3 thin films is reported. Films are deposited under glancing angle deposition (GLAD) configuration of sputtering at varying GLAD angle from 65° to 80°. Structure transition from monoclinic to orthorhombic phase in deposited WO3 films is perceived after ex situ annealing at temperature of 400 °C. Resistive switching properties show shift from bipolar to unipolar switching on postdeposition annealing. WO3 films show unipolar switching behavior after ex situ annealing for all prepared samples. The value of resistance in high resistance state is lowered after ex situ heating treatment and interestingly switching voltage also reduces to 3 V from 7 V after annealing treatment. The ratio of high to low resistance state for annealed WO3 film fabricated at 70° GLAD angle is achieved to be maximum (≈219). A detailed charge transport mechanism shows that ohmic behavior is dominant current conduction mechanism at lower applied voltage, while space charge limited current and Child's law are dominant at higher applied voltages. Obtained results encourage utilization of prepared WO3 thin films toward a wide variety of applications in optoelectronics, microelectronics, and environmental engineering along with advanced electronics such as resistive memory devices. [ABSTRACT FROM AUTHOR]

Circular dichroism is a unique chiroptical signature of the chirality of a system and is a prevalent way to characterize and distinguish systems on a fundamental level and for their technological applicability. Thus, engineering and maximizing the chiroptical response of a single chiral object or a metasurface composed of chiral entities is a formidable task. Current efforts strongly focus on individual metallic nanostructures and their periodic ensembles to harvest on (resonant) plasmonic properties and interactions. This route, however, waives the advantages of high‐refractive‐index nanoscale materials embracing low dissipative losses at optical wavelengths and electromagnetic fields penetrating and propagating in such materials. Herein, a strong circular dichroism is demonstrated in square lattices of nanohelices made of the high‐refractive‐index semiconductor germanium, with dissymmetry factors outperforming metal‐based ensembles. The observation of a much higher dissymmetry emerges for illumination with spatially coherent light, in comparison to spatially incoherent light. High dissymmetry is attributed to cooperative coupling between single helices, resulting from the combination of dielectric resonances of both the individual helical building blocks and the highly ordered lattice. [ABSTRACT FROM AUTHOR]

Vertical ZnO/CuO axial nanowire (NW) arrays were fabricated by using glancing angle deposition technique inside the Radio Frequency (RF) magnetron sputtering system. A post annealing treatment of vertical ZnO/CuO axial NWs was performed in air from 200 °C to 900 °C temperature. Field emission scanning electron microscope imaging shows vertically well aligned NW structure. X-ray diffraction analysis showed improvement in crystalline structure, with increasing annealing with 400 °C sample showing the minimum dislocation density. The annealed sample at 400 °C (in air) shows high photoresponse as compared to other samples signifying reduction in defect states as also observed from photoluminescence analysis. The 400 °C sample showed the highest photocapacitance owing to the improvement in the interface. Moreover, the annealed vertical ZnO/CuO axial NW arrays at 400 °C showed a large responsivity (R) of 2.52 A W−1, specific detectivity (D *) of 5.14 × 1011 Jones and noise equivalent power as low as 6.54 pW at +4 V respectively. Furthermore, the annealed 400 °C device showed fast response with equal rise and fall time of 0.02 ms at +4 V. [ABSTRACT FROM AUTHOR]

Structural chirality has been imposed onto nano‐alloys to introduce diverse new properties. Chiral nanoparticles (CNPs) with the atomic scale chirality are composed of metastable chiral lattices having low thermal stability, so multielementary (>2 elements) CNPs are very challenging to produce using traditional high‐energy fabrication methods. Herein, layer‐by‐layer glancing angle deposition (LbL‐GLAD) at a low substrate temperature of ≈−40 °C, consisting of GLAD of the host CNPs and the subsequent GLAD of guests, is devised to extend the alloy compositional space to the ternary (e.g., Ag:Al:Cu and Ag:Al:Au) and quaternary (e.g., Ag:Al:Cu:Au and Al:In:Sn:Ti). The low‐temperature GLAD‐induced alloying facilitates the formation of the metastable multi‐layer chiral twisting of achiral facets, chiral defects due to the diffusion of the guests, and chiral electronic bands, leading to a significant amplification of chiroplasmonic optical activities in 20–30 folds. The LbL‐GLAD can be generally adapted to fabricate multielementary alloy CNPs composed of a wide range of elements, with a prospective application of asymmetric catalysts to synthesize an enantiomer with designable chirality, one of the most important topics in modern chemistry and biochemistry to solve the problems of health and environmental pollution. [ABSTRACT FROM AUTHOR]