Deposition of Cr Atoms Using Switching-Detuning Light Mask for Direct Atom Lithography

2019 ◽  
Vol 15 (6) ◽  
pp. 626-630
Author(s):  
Li Zhu ◽  
Xiao Deng ◽  
Jie Liu ◽  
Xinbin Cheng ◽  
Tongbao Li
Keyword(s):  
Spatial Frequency ◽  
Deposition Time ◽  
Frequency Doubling ◽  
Deposition Process ◽  
Atom Beam ◽  
High Uniformity ◽  
Dipole Force ◽  
Scaling Down ◽  
Pitch Distance ◽  
Atom Lithography

Background: As progress on the nanofabrication has made semiconductor developed rapidly, there is an increasing need in precise pitch standards to calibrate the structure of devices at nanoscale. Nano-gratings fabricated by atom lithography are unique and suitable to act as precise pitch standard because its pitch distance is directly traceable to a natural constant. As the scaling down of nano-devices, it is very challenging to double the spatial frequency of nano-grating while keeping the self-traceability in atom lithography. Methods: In this study, the switching-detuning light mask is utilized for Cr atom lithography. During a single deposition process, the standing wave frequency is switching from positive detuning to negative detuning alternatively. Results: Nano-gratings fabricated using switching-detuning light mask is successfully replicated with double spatial frequency and self-traceability. Non-uniformity between neighboring Cr lines shows up with a corrected pitch of 107.15 Conclusion: Non-uniformity is mainly caused by the dipole force discrepancy between positive and negative detuning light mask. Therefore, to increase the high uniformity of nano-gratings, the deposition time of negative detuning should be at least twice as the positive detuning. On the other hand, to reduce the pitch uncertainty, it is necessary to reduce the distance between the atom beam and reflection mirror as close as possible. These two significant optimization designs are promising to increase the spatial frequency doubling performance with high uniformity and accuracy.

scholarly journals Preparation and Properties of Mo Coating on H13 Steel by Electro Spark Deposition Process

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3700
Author(s):  
Wenquan Wang ◽  
Ming Du ◽  
Xinge Zhang ◽  
Chengqun Luan ◽  
Yingtao Tian
Keyword(s):  
Corrosion Resistance ◽  
Service Life ◽  
Deposition Time ◽  
Deposition Process ◽  
H13 Steel ◽  
Carbide Phases ◽  
Metallurgical Bonding ◽  
Wear And Corrosion ◽  
Deposition Power ◽  
Wear And Corrosion Resistance

H13 steel is often damaged by wear, erosion, and thermal fatigue. It is one of the essential methods to improve the service life of H13 steel by preparing a coating on it. Due to the advantages of high melting point, good wear, and corrosion resistance of Mo, Mo coating was fabricated on H13 steel by electro spark deposition (ESD) process in this study. The influences of the depositing parameters (deposition power, discharge frequency, and specific deposition time) on the roughness of the coating, thickness, and properties were investigated in detail. The optimized depositing parameters were obtained by comparing roughness, thickness, and crack performance of the coating. The results show that the cross-section of the coating mainly consisted of strengthening zone and transition zone. Metallurgical bonding was formed between the coating and substrate. The Mo coating mainly consisted of Fe9.7Mo0.3, Fe-Cr, FeMo, and Fe2Mo cemented carbide phases, and an amorphous phase. The Mo coating had better microhardness, wear, and corrosion resistance than substrate, which could significantly improve the service life of the H13 steel.

scholarly journals Deposition Time induced Structural and Optical Properties of Lead Tin Sulphide Thin Films

2021 ◽  
pp. 455-458
Author(s):  
J. Damisa ◽  
J. O. Emegha ◽  
I. L. Ikhioya
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Tin Oxide ◽  
Deposition Time ◽  
Deposition Process ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Prepared Material

Lead tin sulphide (Pb-Sn-S) thin films (TFs) were deposited on fluorine-doped tin oxide (FTO) substrates via the electrochemical deposition process using lead (II) nitrate [Pb(NO3)2], tin (II) chloride dehydrate [SnCl2.2H2O] and thiacetamide [C2H5NS] precursors as sources of lead (Pb), tin (Sn) and sulphur (S). The solution of all the compounds was harmonized with a stirrer (magnetic) at 300k. In this study, we reported on the improvements in the properties (structural and optical) of Pb-Sn-S TFs by varying the deposition time. We observed from X-ray diffractometer (XRD) that the prepared material is polycrystalline in nature. UV-Vis measurements were done for the optical characterizations and the band gap values were seen to be increasing from 1.52 to 1.54 eV with deposition time. In addition to this, the absorption coefficient and refractive index were also estimated and discussed.

How Electrophoretic Deposition with Ligand-Free Platinum Nanoparticles Affects Contact Angle

2015 ◽  
Vol 654 ◽  
pp. 218-223 ◽  
Author(s):  
Alexander Heinemann ◽  
Sven Koenen ◽  
Kerstin Schwabe ◽  
Christoph Rehbock ◽  
Stephan Barcikowski
Keyword(s):  
Contact Angle ◽  
Electrophoretic Deposition ◽  
Platinum Nanoparticles ◽  
Deposition Time ◽  
Deposition Process ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Ligand Free ◽  
Vital Parameters ◽  
Scanning Electron

Electrophoretic deposition of ligand-free platinum nanoparticles has been studied to elucidate how wettability, indicated by contact angle measurements, is linked to vital parameters of the electrophoretic deposition process. These parameters, namely the colloid concentration, electric field strength and deposition time, have been systematically varied in order to determine their influence on the contact angle. Additionally, scanning electron microscopy has been used to confirm the homogeneity of the achieved coatings.

Observations on Spatial-Frequency Doubling

Perception ◽  
1974 ◽  
Vol 3 (1) ◽  
pp. 81-86 ◽  
Author(s):  
C W Tyler
Keyword(s):  
Spatial Frequency ◽  
Transient Response ◽  
Frequency Doubling ◽  
Amacrine Cells ◽  
Distortion Model ◽  
Detection Model ◽  
Disparity Detection

The involvement of disparity detectors in the perception of spatial-frequency doubling in a flickering grating was tested by viewing the grating horizontally. Frequency doubling was unimpaired, and must therefore occur independently of disparity detection. A distortion model of frequency doubling was compared with a flicker-detection model, in predicting the appearance of nonsinusoidal gratings. The results support the flicker-detection model but not the distortion model. Physiological considerations suggest that spatial-frequency doubling may be mediated by the transient response of the amacrine cells in the retina.

Magnetron Sputtering Deposition of Calcium Phosphate Films with Nanoscale Grain Morphology in their Surface

2006 ◽  
Vol 975 ◽  
Author(s):  
Wilfredo Otaño ◽  
Víctor M. Pantojas ◽  
Juan M. Figueroa ◽  
Darimar Hernández ◽  
Alejandro Rodríguez-Navarro
Keyword(s):  
Calcium Phosphate ◽  
Surface Morphology ◽  
Magnetron Sputtering ◽  
Deposition Time ◽  
Grain Morphology ◽  
Average Diameter ◽  
Deposition Process ◽  
Medical Implants ◽  
Sputtering Deposition ◽  
Coated Implant

ABSTRACTHydroxyapatite (HA) is a calcium phosphate mineral analogous to the mineral part of bone. This similarity makes this material bioactive and suitable to coat medical implants. However, at present, there is not a coating technique which gives the coated implant the desired properties and long life required for medical implants.In an effort to produce HA coatings with improved properties, calcium phosphate films were prepared using magnetron sputtering deposition on a silicon substrate at 600°C. Initial efforts resulted in the deposition of amorphous films with a distinctive grain-like surface morphology. The morphological grain size was studied using SEM and found that it was possible to control the average diameter value of the round shaped grains by adjusting the deposition time. Increasing the deposition time increases the mean grain diameter. EDS spectra showed the unintentional addition of carbon, iron and nickel to the samples during deposition. After eliminating the impurities, it was possible to prepare calcium phosphate films in the HA phase but without the grain-like surface morphology. These results suggested that the impurities prevented the formation of the calcium phosphate HA phase while acting as nuclei for the heterogeneous nucleation of the grains. This is an important result where the deposition process parameters can be controlled to functionalize the films in order to produce distinctive nanoscale features in the surface morphology.

The Effect of Inoculum in the Preparation of Fermented Tapioca for Nanotechnology Applications Based on FT-IR Studies

2013 ◽  
Vol 667 ◽  
pp. 534-537
Author(s):  
M.Z. Nuraini ◽  
S. Aishah ◽  
S.F. Nik ◽  
Mohamad Rusop
Keyword(s):  
Carbon Nanotubes ◽  
Gas Flow ◽  
Deposition Time ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Ir Studies ◽  
Multi Walled Carbon Nanotubes ◽  
Ft Ir ◽  
Walled Carbon Nanotubes ◽  
Ft Ir Spectroscopy

Fermented tapioca which is a new starting material was used as a carbon precursor. Carbon nanotubes (CNTs) were deposited on silicon wafer (Si) by Thermal Chemical Vapor Deposition (TCVD). The gas flow of Argon (Ar) was constant at 70 bubbles per minute and 20 minutes of deposition time. Before the deposition process, silicon was coated with Nickel using spin coater. Various parameters such as amount of inoculums have been studied. Chemical functional groups of carbon nanotubes were characterized using FT-IR Spectroscopy. The FT-IR result shows peaks attributed to multi–walled carbon nanotubes (MWCNT) vibration modes.

Insights for mfVEPs from perimetry using large spatial frequency-doubling and near frequency-doubling stimuli in glaucoma

2020 ◽  
Vol 141 (1) ◽  
pp. 45-55
Author(s):  
Siti Nurliyana Abdullah ◽  
Gordon F. Sanderson ◽  
Mohd Aziz Husni ◽  
Ted Maddess
Keyword(s):  
Spatial Frequency ◽  
Frequency Doubling

Threshold Value of Particle Concentration in EPD: Experimental Evidence with TiO2 Organic Suspensions

2009 ◽  
Vol 412 ◽  
pp. 51-56 ◽  
Author(s):  
Simona Radice ◽  
Stefano Mischler ◽  
Johann Michler
Keyword(s):  
Particle Concentration ◽  
Deposition Time ◽  
Threshold Value ◽  
Deposition Process ◽  
Suspension Systems ◽  
Limit Value ◽  
Coating Formation ◽  
Concentration Threshold

This study was triggered by our experience on electrophoretic deposition (EPD) with different suspension systems showing evidence of a particle concentration threshold, below which no deposit was formed. In this study, the role of particle concentration in the mechanism of EPD was investigated with a model system, consisting of isopropanol suspensions with TiO2 nanosized particles (d50 = 130 nm). The investigated concentration range was 0.01 - 0.4 vol% TiO2. Constant voltage EPD tests with variable particle concentration were performed for 1 min under different applied voltages (25 - 300 V corresponding to 62.5 - 750 V/cm). A longer deposition time (30 min) was tested for a lower concentration value (0.003 vol% TiO2). The deposition process was evaluated in situ by means of the current measured during EPD. The deposits obtained were characterized by weight and profile measurements and scanning electron microscope (SEM). The results confirmed the finding of a lower limit value of particle concentration, determining a threshold in the formation of an EPD coating. Above this threshold, proportionality between deposited mass and particle concentration was observed, in agreement with the equation of Hamaker. Below this threshold, the proportionality was lost with evidence of a lack of coating formation. A possible interpretation for this experimental finding was provided.

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