scholarly journals Tailoring the nanoscale morphology of HKUST-1 thin films via codeposition and seeded growth

2017 ◽  
Vol 8 ◽  
pp. 2307-2314 ◽  
Author(s):  
Landon J Brower ◽  
Lauren K Gentry ◽  
Amanda L Napier ◽  
Mary E Anderson

Integration of surface-anchored metal-organic frameworks (surMOFs) within hierarchical architectures is necessary for potential sensing, electronic, optical, or separation applications. It is important to understand the fundamentals of film formation for these surMOFs in order to develop strategies for their incorporation with nanoscale control over lateral and vertical dimensions. This research identified processing parameters to control the film morphology for surMOFs of HKUST-1 fabricated by codeposition and seeded deposition. Time and temperature were investigated to observe film formation, to control film thickness, and to tune morphology. Film thickness was investigated by ellipsometry, while film structure and film roughness were characterized by atomic force microscopy. Films formed via codeposition resulted in nanocrystallites anchored to the gold substrate. A dynamic process at the interface was observed with a low density of large particulates (above 100 nm) initially forming on the substrate; and over time these particulates were slowly replaced by the prevalence of smaller crystallites (ca. 10 nm) covering the substrate at a high density. Elevated temperature was found to expedite the growth process to obtain the full range of surface morphologies with reasonable processing times. Seed crystals formed by the codeposition method were stable and nucleated growth throughout a subsequent layer-by-layer deposition process. These seed crystals templated the final film structure and tailor the features in lateral and vertical directions. Using codeposition and seeded growth, different surface morphologies with controllable nanoscale dimensions can be designed and fabricated for integration of MOF systems directly into device architectures and sensor platforms.

2005 ◽  
Vol 901 ◽  
Author(s):  
Junghyun Cho ◽  
Douglas A. Blom ◽  
Dorothy W. Coffey ◽  
Lawrence F. Allard ◽  
Junghyun Cho

AbstractA biomimetic approach is employed to deposit ceramic films on organic self-assembled monolayers (SAMs) coated substrates. Specifically, zirconia (ZrO2) films are grown in a zirconium sulfate precursor solution at near room temperatures (∼70°C). This process, directed by the nanoscale organic template, mimics the controlled nucleation and growth of the biominerals such as bones and teeth. The resultant zirconia films consist of nanosized particles (5-10 nm) that are precipitated out in a supersaturated precursor solution. Cross-sectional TEM and STEM works were performed to quantitatively analyze the film structure and chemistry, as well as interfacial region of the ceramic-SAM films. A stepwise deposition process was developed to avoid excessive formation of aggregation. Further, the dynamic nanoindentation testing was employed to assess the thickness and film-only intrinsic mechanical properties for direct comparison among the films processed with different processing parameters and microstructures. The films with finer particulate structure displayed higher intrinsic modulus than did those with coarser structure.


2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
M. Selin Sunay ◽  
Onder Pekcan ◽  
Saziye Ugur

Steady-state fluorescence (SSF) technique in conjunction with UV-visible (UVV) technique and atomic force microscope (AFM) was used for studying film formation from TiO2covered nanosized polystyrene (PS) latex particles (320 nm). The effects of film thickness and TiO2content on the film formation and structure properties of PS/TiO2composites were studied. For this purpose, two different sets of PS films with thicknesses of 5 and 20 μm were prepared from pyrene-(P-) labeled PS particles and covered with various layers of TiO2using dip-coating method. These films were then annealed at elevated temperatures above glass transition temperature () of PS in the range of 100–280°C. Fluorescence emission intensity, from P and transmitted light intensity, were measured after each annealing step to monitor the stages of film formation. The results showed that film formation from PS latexes occurs on the top surface of PS/TiO2composites and thus developed independent of TiO2content for both film sets. But the surface morphology of the films was found to vary with both TiO2content and film thickness. After removal of PS, thin films provide a quite ordered porous structure while thick films showed nonporous structure.


Langmuir ◽  
2008 ◽  
Vol 24 (19) ◽  
pp. 10851-10857 ◽  
Author(s):  
Lianbin Zhang ◽  
Yang Li ◽  
Junqi Sun ◽  
Jiacong Shen

Langmuir ◽  
2013 ◽  
Vol 29 (7) ◽  
pp. 2159-2165 ◽  
Author(s):  
Abhijit Bera ◽  
Sukumar Dey ◽  
Amlan J. Pal

Lab on a Chip ◽  
2016 ◽  
Vol 16 (23) ◽  
pp. 4601-4611 ◽  
Author(s):  
Ziye Dong ◽  
Ling Tang ◽  
Caroline C. Ahrens ◽  
Zhenya Ding ◽  
Vi Cao ◽  
...  

We report a benchtop platform to systematically study film thickness, surface roughness, biocompatibility and degradation of a series of biodegradable nanolayered films.


1986 ◽  
Vol 64 (10) ◽  
pp. 1369-1373 ◽  
Author(s):  
U. von Sacken ◽  
D. E. Brodie

The structure of polycrystalline Zn3P2 films has been studied for 1- to 2-μm-thick vacuum-deposited films on glass substrates. Transmission electron microscopy and X-ray diffraction techniques have been used to obtain a detailed, quantitative analysis of the film structure. The initial growth consists of small (≤ 10 nm), randomly oriented grains. As the film thickness increases, the growth of crystallites with the {220} planes oriented approximately parallel to the substrate is favoured, and a columnar structure develops along with a highly preferred orientation. This structure has been observed directly by transmission electron microscopy of thin cross sections of the films. The size of the grains at the free surface increases with the film thickness, reaching approximately 200–300 nm when the film is 1 μm thick. The effects of substrate temperature and low-energy (0.5–2 keV) electron bombardment of the film during growth have also been studied. Neither substrate temperature nor electron bombardment appear to have a major effect on the film structure. The primary effect of electron bombardment appears to be the creation of preferred nucleation sites on the substrate.


2009 ◽  
Vol 1153 ◽  
Author(s):  
Yuri Vygranenko ◽  
Ehsanollah Fathi ◽  
Andrei Sazonov ◽  
Manuela Vieira ◽  
Gregory Heiler ◽  
...  

AbstractWe report on structural, electronic, and optical properties of boron-doped, hydrogenated nanocrystalline silicon (nc-Si:H) thin films deposited by plasma-enhanced chemical vapor deposition (PECVD) at a substrate temperature of 150°C. Film properties were studied as a function of trimethylboron-to-silane ratio and film thickness. The film thickness was varied in the range from 14 to 100 nm. The conductivity of 60 nm thick films reached a peak value of 0.07 S/cm at a doping ratio of 1%. As a result of amorphization of the film structure, which was indicated by Raman spectra measurements, any further increase in doping reduced conductivity. We also observed an abrupt increase in conductivity with increasing film thickness ascribed to a percolation cluster composed of silicon nanocrystallites. The absorption loss of 25% at a wavelength of 400 nm was measured for the films with optimized conductivity deposited on glass and glass/ZnO:Al substrates. A low-leakage, blue-enhanced p-i-n photodiode with an nc-Si p-layer was also fabricated and characterized.


1999 ◽  
Vol 592 ◽  
Author(s):  
T. Hattori ◽  
H. Nohira ◽  
Y Teramoto ◽  
N. Watanabe

ABSTRACTThe interface state densities near the midgap were measured with the progress of oxidation of atomically flat Si(100) surface. It was found that the interface state distribution in Si bandgap changes periodically with the progress of oxidation. Namely, the interface-state density near the midgap of Si exhibits drastic decrease at oxide film thickness where the surface roughness of oxide film takes its minimum value, while that does not exhibit decrease at the oxide film thickness where the surface roughness takes its maximum value. In order to minimize interface state densities the oxide film thickness should be precisely controlled to within an accuracy of 0.02 nm.


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