Dry Deposition Technique Research Articles

Liquid-Phase Fabrication of Janus 2D Materials: Defect-Rich MoS2 Ultrathin Layers Asymmetrically Decorated with Au Nanoparticles.

Asymmetrically decorated nanoparticles (NPs), also known as "Janus nanoparticles", possess at least two differently functionalized surfaces. This coexistence results in novel features that surpass the inherited benefits of the initial counterparts. Despite significant advances in spherical morphologies, research on Janus two-dimensional (2D) materials is limited, as fabrication strategies primarily focus on dry deposition techniques. To produce Janus 2D materials in large quantities, solution-based techniques are proposed. However, this approach remains largely unexplored for 2D materials other than graphene and its derivatives, and it yields Janus 2D materials in very low amounts. This study develops a liquid-phase fabrication strategy for the asymmetric decoration of MoS2 ultrathin layers with gold nanoparticles. This approach builds on previous advances in the asymmetric functionalization of spherical nanoparticles, using SiO2 microbeads as a masking template. Interestingly, the photoluminescence (PL) spectrum of the processed material is unusually dominated by the B exciton emission. The reported versatile method has proven to be scalable, enabling the production of 2D Janus flakes in appreciable quantities, whether as 1T or 2H-polytypes. Overall, the novel synthetic strategy is highly adaptable and can be extended to a variety of other 2D materials and functionalizing agents.

Wafer-Scale Fabrication of Wearable All-Carbon Nanotube Photodetector Arrays.

With electronic devices evolving toward portable and high-performance wearables, the constraints of complex and wet processing technologies become apparent. This study presents a scalable photolithography/chemical-free method for crafting wearable all-carbon nanotube (CNT) photodetector device arrays. Laser-assisted patterning and dry deposition techniques directly assemble gas-phase CNTs into flexible devices without any lithography or lift-off processes. The resulting wafer-scale all-CNT photodetector arrays showcase excellent uniformity, wearability, environmental stability, and notable broadband photoresponse, boasting a high responsivity of 44 AW-1 and a simultaneous detectivity of 1.9 × 109 Jones. This research provides an efficient, versatile, and scalable strategy for manufacturing wearable all-CNT device arrays, allowing widespread adoption in wearable optoelectronics and multifunctional sensors.

Preparation, optimization and electrochromic properties of dual-band device with four modes

A dual-band electrochromic device with four modes was fabricated to selective modulate the transmittance from visible to near-infrared bands for the energy-saving field. The new LiClO4 + TBACl + AgNO3 electrolyte was prepared to respectively regulate the redox reactions of silver ion and lithium ion to prove the four modes of the device. The dual-band device with a sandwich structure was fabricated by the titanium dioxide electrochromic film, the gallium doped zinc oxide ion storage film and the LiClO4 + TBACl + AgNO3 electrolyte. The titanium dioxide and gallium doped zinc oxide films were prepared by a nanoparticle deposition system, which is an environmentally friendly dry deposition technique. By controlling the supplied potential, the redox reactions of silver ion and lithium ion present four modes, including transparent mode, warm mode, cold mode and full block mode. For warm mode, the localized surface plasmon resonance effect was excited by generating silver nanoparticles using two-stage potential. Moreover, the titanium dioxide film with high surface roughness shown the large light scattering effect, the transmittance of ∼0% at whole wavelengths was obtained in full block mode. The electrochromic device shown the large transmittance modulation (71%) and excellent cyclic stability (600 cycles). Therefore, it is proved that the transmittance can be adjusted at a specific wavelength by the electrochromic device, which provides an effective way for developing dual-band smart devices to reduce energy consumption.

A Review on Dry Deposition Techniques: Pathways to Enhanced Perovskite Solar Cells

This review discusses the use of evaporation, chemical vapor deposition, and sputtering as the three main dry deposition techniques currently available for fabricating perovskite solar cells. We outline the distinct advantages that each method offers in terms of film quality, control, and scalability. Additionally, recent advancements in process optimization and the integration of dry deposition with other fabrication techniques are highlighted. Thus, this review provides valuable insights into the potential of dry deposition processes to produce high-performance perovskite solar cells and aids researchers and industry professionals in selecting the most suitable technique for the fabrication of efficient and stable devices.

ScAlN Thick-Film Ultrasonic Transducer in 40-80 MHz.

A medical ultrasound diagnostic system and an ultrasonic microscope are generally used in the frequency range of 1-20 MHz and 100 MHz-2 GHz, respectively. Ultrasonic transducers in the frequency range of 20-100 MHz are, therefore, not well developed because of less application into ultrasonic imaging or suitable piezoelectric materials with this frequency range. Polyvinylidene difluoride (PVDF) is usually used for ultrasonic transducers in the 10-50-MHz ranges. However, their electromechanical coupling coefficient of 4% is not enough for the practical uses. In order to excite the ultrasonic wave in the 20-100 MHz range, a 125-25- -thick piezoelectric film is required when the longitudinal velocity of the material is assumed to be 5000 m/s. However, it is difficult to grow such a thick piezoelectric film without a crack being caused by the internal stress during the dry deposition technique. We achieved a stress-free film growth by employing the unique hot target sputtering technique without heating the substrate. High-efficient 81- ( .5%) and 43-MHz ( %) ultrasonic generation by using the 43- and 90- extremely thick ScAlN (Sc: 39%) films were demonstrated, respectively. We discussed the advantage of ScAlN thick-film transducers by comparing them with the conventional PVDF transducer for the water medium.

Local and Global Volumetric Strain Comparison in Sand Specimens Subjected to Drained Cyclic and Monotonic Triaxial Compression Loading

This article investigates the development of volumetric strain nonuniformities in sand specimens subjected to drained cyclic triaxial compression loading. The assessment is performed by comparing volumetric strain determinations using an external volume gauge and local axial and radial strain measurements mounted on the center of the specimen. The experimental investigation has been performed for both frictional and enlarged lubricated ends on sand specimens of different densities and fabricated using both moist tamping and dry deposition techniques. It will be shown that considerable discrepancies between the global and local volumetric determination arise even in specimens tested with enlarged lubricated ends, as a result of different volumetric tendencies (contraction or dilation) of the center and the boundaries of the specimens. These discrepancies are more pronounced for dense specimens cycled at high average stress ratios and amplitudes. The influence of three different assumptions employed to account for the specimen’s deformed profile (namely the right cylinder, parabolic, and sinusoidal profile) on the local volumetric determinations will be also assessed. Some recommendations for the need for local volumetric measurements will be attempted.

SOME TECHNICAL ASPECTS OF THE RHEOLOGICAL PROPERTIES OF HIGH CONCENTRATION FINE SUSPENSIONS TO AVOID ENVIRONMENTAL DISASTERS

The behavior of slurries and suspensions made by mixing solid particles and liquids is very important for various industrial applications. The latest accidental failure events at tailings facilities (Kolontár, Baia Mare) have focused public interest into this field. Nowadays, environmental practice is turning to use dry deposition techniques or at least as high concentration slurries or pastes as possible, to avoid large spills in case of an accidental failure of an embankment. High concentration slurries are becoming widely accepted in many environmentally related operations such as underground backfilling or simple tailings deposition. However, the hydraulic transport of pastes or high density slurries requires higher energy input via pumps, and, in addition, the energy requirement or pressure loss calculation methods are also different because the rheology of pastes differs from that of dilute slurries. At the University of Miskolc, Institute of Raw Materials Preparation and Environmental Processing, Miskolc, Hungary, this topic has been studied for many decades. The fine suspension – coarse mixture flow model was introduced, and it has been determined that the flow behavior of fine suspensions made of solid particles smaller than a limit particle size can be measured and interpreted in almost the same way as for single phase clear liquids. Based on these measured rheological parameters of fine suspensions, the frictional energy loss can be calculated. The aim of this paper is to give a summary and data base about the rheological behavior of different industrial materials based on pilot scale hydraulic loop measurements. An Anton-Paar rotational viscometer and a tube viscometer with three measuring pipe sections,– developed by our institute – were used for testing. The results of measurements of various granular materials, such as sands, fly ashes, perlite, tailings and red mud are presented in connection with environmental applications. Based on these results, empirical relationships are presented, where the parameters are determined by simple function fitting into the data of measurements carried out at discrete concentration values. The rheology of fine suspensions of any concentration up to the measured maximum can be calculated by these relationships.

Monotonic and Cyclic Behavior of Chiang Mai Sand Under Simple Shear Mode

Record of damages and casualties caused by earthquakes in Thailand reveals that Chiang Mai, the second largest province of Thailand, has faced the great threat among other provinces. Triaxial tests, standard penetration tests, and multichannel analysis of surface wave have been recently performed to understand the dynamic response of Chiang Mai ground. However, the cyclic simple shear test, which could convincingly represent the real seismic ground shaking under repeated horizontal shear force, has not been conducted yet. Therefore, this paper aims to characterize the behaviors of Chiang Mai sand under monotonic and cyclic loadings using a direct simple shear apparatus. Sand specimens taken from the Ping River were prepared by dry deposition technique. The mobilized friction angle at the critical state measured by the direct simple shear test is equal to 37.3° which is 9 % less than that measured by direct shear box test. This paper also provides the appropriate dynamic properties of Chiang Mai sand with the shear strain level <2 % for any practical purpose. Test results showed that the normalized shear modulus agrees well with other investigators while the damping ratio is noticeably smaller than the lower-bound range for sand reported in the past studies.

Microstructure and Durability of Non-Carbon Supported Cathode Prepared by a Direct Dry Deposition Technique

not Available.

Supported and unsupported platinum catalysts prepared by a one-step dry deposition method and their oxygen reduction reactivity in acidic media

The present study examines the physical and electrochemical properties of platinum particles generated by a combustion method for use in oxygen reduction on the cathode side of a proton exchange fuel cell (PEMFC). This method employs a one-step, open-atmosphere, and dry deposition technique called reactive spray deposition technology (RSDT). The objective of this study is to characterize the intrinsic activity of the platinum produced for incorporation into low-loading cathode electrodes in high performing membrane electrode assemblies (MEA). The process allows for independent real-time control of the carbon, platinum, and ionomer ratios in the final electrode. In this research work we examine the oxygen reduction reaction via a rotating disk three electrode set-up to understand the intrinsic activity of the as-sprayed platinum as well as platinum condensed onto a carbon support. The mass and specific activities were measured in a 0.1 M perchloric acid electrolyte under different deposition conditions and loading was verified by atomic emission spectroscopy inductively coupled plasma (AES-ICP). Microscopy results indicate that the platinum particle sizes are 5 nm (σ = 2.8 nm) in diameter while TEM and XRD show that the platinum generated by the process is pure and crystalline without bulk oxides or precursor material present. The initial rotating disk electrode result shows that the RSDT technique is capable of producing catalysts with an oxygen reduction mass activity at 0.9 V of 200 mA/mgPt rotating at 1600 rpm and 30 °C. The electrochemically active surface area approaches 120 m2/g for the platinum, carbon, and ionomer samples and the unsupported sample with only platinum has an active area of 92 m2/g. The rather larger surface area of the unsupported sample exists when the platinum is deposited as a highly porous nanostructured layer that allows for high penetration of reactant.

Activity and Microstructure of Oxygen Evolution Anodes Prepared by a Direct Dry Deposition Technique

not Available.

Direct fabrication of integrated 3D Au nanobox arrays by sidewall deposition withcontrollable heights and thicknesses

This paper provides a unique strategy for controlling integrated hollow nanostructurearrays such as boxes or pillars at the nanometer scale. The key merit of this technique isthat it can overcome resolution limits by sidewall deposition and deposit various materialsusing a sputtering method. The sputtering method can be replaced by other dry depositiontechniques such as pulsed laser deposition (PLD) for complex functional materials.Furthermore, it can produce low-cost large-area fabrication and high reproducibility usingthe NIL (nanoimprint lithograph) process. The fabrication method consists of asequence of bilayer spin-coating, UV-NIL, RIE (reactive ion etching), sputtering,ion milling and piranha cleaning processes. By changing the deposition time andmolds, various thicknesses and shapes can be fabricated, respectively. Furthermore,the fabricated Au box nanostructure has a bending zone of the top layer and a∼17 nm undercut of the bottom layer as observed by SEM (scanning electron microscope). Thesidewall thickness was changed from 12 to 61 nm by controlling the deposition time, andwas investigated to understand the relationship with blanket thicknesses and geometriceffects. The calculated sidewall thickness matched well with experimental results. Usingsmaller hole-patterned molds, integrated nanobox arrays, with inner squares measuring∼160 nm, and nanopillar arrays, with inside pores measuring∼65 nm, were fabricated under the same conditions.

Preparing Gas-Diffusion Layers of PEMFCs with a Dry Deposition Technique

To improve the ease of production and reproducibility, a novel approach was developed for preparing gas-diffusion layers (GDL) of proton-exchange membrane fuel cells (PEMFCs). In this approach, the GDL was prepared by drydeposition of a mixture of carbon black and polytetrafluoroethylene powders onto water-proofed carbon paper in combination with a subsequent rolling process. Three kinds of carbon black, including Ketjenblack EC-600JD, Vulcan XC-72, and Denka, were investigated. Furthermore, the reproducibility of the GDL with Vulcan XC-72 was also tested. The results indicate that this dry-deposition technique is feasible for mass production applications with simple operation, solvent-free coating and excellent repeatability.

Metallization by plating for high-performance multichip modules

Electrolytic plating is used to produce the interconnect wiring on the current generation of high-performance multichip modules used in IBM S/390® and AS/400® servers. This paper reviews the material and manufacturing requirements for successful implementation of a multilayer high-density wiring pattern involving electroplated copper metal and polyimide dielectric. Various strategies for the construction of thin-film structures (planarized and nonplanarized) are outlined, and the advantages of electrolytic plating over dry deposition techniques are described.