scholarly journals Formation Mechanism of Well-Ordered Densely Packed Nanoparticle Superlattices Deposited from Gas Phase on Template-Free Surfaces

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Chang Liu ◽  
Fei Liu ◽  
Chen Jin ◽  
Sishi Zhang ◽  
Lianhua Zhang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Formation Mechanism ◽  
Substrate Surface ◽  
Deposition Process ◽  
Solution Chemistry ◽  
Two Dimensional ◽  
Self Assembled Monolayer ◽  
Free Surfaces ◽  
Phase Cluster ◽  
Template Free

AbstractSuperlattices of nanoparticles are generally produced based on solution chemistry processes. In this paper, we demonstrate that self-assembled monolayer structures of nanoparticles with superlattice periodicities can also be produced on template-free surfaces in the gas-phase cluster beam deposition process. It is found that the packing of Fe nanoparticles corresponds to an average of two-dimensional densely packed lattice with a hexagonal summary. By controlling the nanoparticle coverage, the two-dimensional densely packed monolayer morphology can spread to the whole substrate surface being deposited. A formation mechanism of the ordered monolayers is proposed. The densely packed morphologies are formed by the balance between the diffusion rate of the nanoparticles and their filling speed on the substrate surface determined by the deposition rate, and the ordering of the nanoparticle arrays is driven by the inter-particle attractive interactions. The model is strongly supported by a series of carefully designed cluster deposition experiments.

scholarly journals Formation Mechanism of Well-Ordered Densely Packed Nanoparticle Superlattices Deposited from Gas Phase on Template-Free Surfaces

2021 ◽  
Author(s):  
Chang Liu ◽  
Fei Liu ◽  
Chen Jin ◽  
Sishi Zhang ◽  
Lianhua Zhang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Formation Mechanism ◽  
Substrate Surface ◽  
Deposition Process ◽  
Solution Chemistry ◽  
Two Dimensional ◽  
Self Assembled Monolayer ◽  
Free Surfaces ◽  
Phase Cluster ◽  
Template Free

Abstract Superlattices of nanoparticles are generally produced based on solution chemistry processes. In this paper, we demonstrate that self-assembled monolayer structures of nanoparticles with superlattice periodicities can also be produced on template-free surfaces in the gas phase cluster beam deposition process. It is found the packing of Fe nanoparticles corresponds to an average two-dimensional densely-packed lattice with a hexagonal summary. By controlling the nanoparticle coverage, the two-dimensional densely-packed monolayer morphology can spread to the whole substrate surface being deposited. A formation mechanism of the ordered monolayers is proposed by considering the balance between the diffusion rate of the nanoparticles and their filling speed on the substrate surface determined by the deposition rate, and the ordering driven by the inter-particle attractive forces. The model is strongly supported by a serial of carefully designed cluster deposition experiments.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

scholarly journals Template-Free Self-Assembly of Two-Dimensional Polymers into Nano/Microstructured Materials

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3310
Author(s):  
Shengda Liu ◽  
Jiayun Xu ◽  
Xiumei Li ◽  
Tengfei Yan ◽  
Shuangjiang Yu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Recent Progress ◽  
Two Dimensional ◽  
Subsequent Removal ◽  
The Past ◽  
2D Polymers ◽  
Template Free ◽  
Self Assembled ◽  
The Relationship ◽  
Polymer Tubes

In the past few decades, enormous efforts have been made to synthesize covalent polymer nano/microstructured materials with specific morphologies, due to the relationship between their structures and functions. Up to now, the formation of most of these structures often requires either templates or preorganization in order to construct a specific structure before, and then the subsequent removal of previous templates to form a desired structure, on account of the lack of “self-error-correcting” properties of reversible interactions in polymers. The above processes are time-consuming and tedious. A template-free, self-assembled strategy as a “bottom-up” route to fabricate well-defined nano/microstructures remains a challenge. Herein, we introduce the recent progress in template-free, self-assembled nano/microstructures formed by covalent two-dimensional (2D) polymers, such as polymer capsules, polymer films, polymer tubes and polymer rings.

Patterning Organic Fluorescent Molecules with SAM Patterns

2011 ◽  
Vol 1335 ◽  
Author(s):  
Qiong Wu ◽  
Juanyuan Hao ◽  
Shoulei Shi ◽  
Weifeng Wang ◽  
Nan Lu
Keyword(s):  
Organic Molecules ◽  
Low Cost ◽  
Substrate Surface ◽  
Large Area ◽  
Self Assembled Monolayer ◽  
Storage Duration ◽  
Light Emitting ◽  
High Throughput Method ◽  
Self Assembled ◽  
Fluorescent Molecules

ABSTRACTWe report a low-cost and high-throughput method to fabricate large-area light emitting pattern via thermal evaporation of organic molecules on the patterned self-assembled monolayer of homogenous 3-aminopropyltrimethoxysilane. This method is based on the selective deposition of the organic light emitting molecules on the template of self-assembled monolayer (SAM), which is patterned with nanoimprinting lithography. The selectivity can be controlled by adjusting the design of the pattern, the storage duration and the substrate temperature. The deposition selectivity of the molecules may be caused by the different binding energy of the molecules with the SAM and the substrate surface.

Thermochemical stabilities of the gas-phase cluster ions H3C+(N2)n

2003 ◽  
Vol 227 (3) ◽  
pp. 391-399 ◽  
Author(s):  
Kenzo Hiraoka ◽  
Kiyotoshi Takao ◽  
Fumiyuki Nakagawa ◽  
Tomoyuki Iino ◽  
Masayumi Ishida ◽  
...  
Keyword(s):  
Gas Phase ◽  
Cluster Ions ◽  
Phase Cluster

Numerical Analysis of Two-Phase Pipe Flow of Liquid Helium Using Multi-Fluid Model

2001 ◽  
Vol 123 (4) ◽  
pp. 811-818 ◽  
Author(s):  
Jun Ishimoto ◽  
Mamoru Oike ◽  
Kenjiro Kamijo
Keyword(s):  
Phase Transition ◽  
Gas Phase ◽  
Liquid Helium ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Numerical Results ◽  
Phase Flow ◽  
Two Dimensional ◽  
Two Phase ◽  
Normal Fluid

The two-dimensional characteristics of the vapor-liquid two-phase flow of liquid helium in a pipe are numerically investigated to realize the further development and high performance of new cryogenic engineering applications. First, the governing equations of the two-phase flow of liquid helium based on the unsteady thermal nonequilibrium multi-fluid model are presented and several flow characteristics are numerically calculated, taking into account the effect of superfluidity. Based on the numerical results, the two-dimensional structure of the two-phase flow of liquid helium is shown in detail, and it is also found that the phase transition of the normal fluid to the superfluid and the generation of superfluid counterflow against normal fluid flow are conspicuous in the large gas phase volume fraction region where the liquid to gas phase change actively occurs. Furthermore, it is clarified that the mechanism of the He I to He II phase transition caused by the temperature decrease is due to the deprivation of latent heat for vaporization from the liquid phase. According to these theoretical results, the fundamental characteristics of the cryogenic two-phase flow are predicted. The numerical results obtained should contribute to the realization of advanced cryogenic industrial applications.

Laser-Induced Selective Copper Deposition on Polyimides and Semiconductors

1992 ◽  
Vol 282 ◽  
Author(s):  
Seong-Don Hwang ◽  
S. S. Kher ◽  
J. T. Spencer ◽  
P. A. Dowben
Keyword(s):  
Gas Phase ◽  
Copper Chloride ◽  
Copper Deposition ◽  
Copper Films ◽  
Liquid Phase Deposition ◽  
Metal Thin Films ◽  
Selective Area ◽  
Phase Cluster ◽  
Photolytic Decomposition ◽  
Area Deposition

ABSTRACTIt has been demonstrated that copper can be selectively deposited on a variety of substrates including Teflon (polytetrafluroethylene or PTFE), Kapton (polyimide resin), silicon and gallium arsnide from solution by photo-assisted initiated deposition. A copper containing solution was prepared from a mixture of copper(I) chloride (Cu2Ci2) and decaborane (B10H14) in diethyl ether and/or THF (tetrahydrofuran). The copper films were fabricated by ultraviolet photolytic decomposition of copper chloride and polyhedral borane clusters. This liquid phase deposition has a gas-phase cluster analog that also results in copper deposition via pyrolysis. The approach of depositing metal thin films selectively by pholysis from solution is a novel and an underutilized approach to selective area deposition.

scholarly journals Pseudo steady states of HONO measured in the nocturnal marine boundary layer: a conceptual model for HONO formation on aqueous surfaces

2011 ◽  
Vol 11 (7) ◽  
pp. 3243-3261 ◽  
Author(s):  
P. Wojtal ◽  
J. D. Halla ◽  
R. McLaren
Keyword(s):  
Conceptual Model ◽  
Gas Phase ◽  
Formation Mechanism ◽  
Marine Boundary Layer ◽  
Steady States ◽  
Optical Absorption Spectroscopy ◽  
Aqueous Environment ◽  
Ambient Atmosphere ◽  
Mass Source ◽  
Aqueous Surfaces

Abstract. A complete understanding of the formation mechanism of nitrous acid (HONO) in the ambient atmosphere is complicated by a lack of understanding of processes occurring when aqueous water is present. We report nocturnal measurements of HONO, SO2 and NO2 by differential optical absorption spectroscopy over the ocean surface in a polluted marine environment. In this aqueous environment, we observed reproducible pseudo steady states (PSS) of HONO every night, that are fully formed shortly after sunset, much faster than seen in urban environments. During the PSS period, HONO is constant with time, independent of air mass source and independent of the concentration of NO2. The independence of HONO on the concentration of NO2 implies a 0° order formation process, likely on a saturated surface, with reversible partitioning of HONO to the gas phase, through vaporization and deposition to the surface. We observed median HONO/NO2 ratios starting at 0.13 at the beginning of the PSS period (with an apparent lower bound of 0.03), rising to median levels of ~0.30 at the end of the PSS period (with an upper bound >1.0). The implication of these numbers is that they suggest a common surface mechanism of HONO formation on terrestrial and aqueous surfaces, with an increase in the HONO/NO2 ratio with the amount of water available at the surface. The levels of HONO during the nocturnal PSS period are positively correlated with temperature, consistent with a partitioning of HONO from the surface to the gas phase with an apparent enthalpy of vaporization of ΔHSNL (HONO)=55.5±5.4 kJ mol−1. The formation mechanism on aqueous surfaces is independent of relative humidity (RH), despite observation of a negative HONO-RH correlation. A conceptual model for HONO formation on ambient aqueous surfaces is presented, with the main elements being the presence of a surface nanolayer (SNL), highly acidic and saturated with N(IV) precursors, production of HNO3, that diffuses to underlying water layers, and HONO, which partitions reversibly between the SNL and the gas phase. Implications of the conceptual model are discussed.

Theoretical Study of Gas-Phase Thermodynamics Relevant to Silicon Carbide Chemical Vapor Deiposition

1991 ◽  
Vol 250 ◽  
Author(s):  
Mark D. Allendorf ◽  
Carl F. Melius
Keyword(s):  
Silicon Carbide ◽  
Gas Phase ◽  
Theoretical Study ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Equilibrium Calculations

AbstractEquilibrium calculations are reported for conditions typical of silicon carbide (SiC) deposition from mixtures of silane and hydrocarbons. Included are 34 molecules containing both silicon and carbon, allowing an assessment to be made of the importance of organosilicon species (and organosilicon radicals in particular) to the deposition process. The results are used to suggest strategies for improved operation of SiC CVD processes.

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