Unexpected Precipitates in Conjunction with Layer-by-Layer Growth in Mn-Enriched La2/3Sr1/3MnO3 Thin Films

Metal organic frameworks have emerged as an important new class of materials with many applications, such as sensing, gas separation, drug delivery. In many cases, their performance is limited by structural defects, including vacancies and domain boundaries. In the case of MOF thin films, surface roughness can also have a pronounced influence on MOF-based device properties. Presently, there is little systematic knowledge about optimal growth conditions with regard to optimal morphologies for specific applications. In this work, we simulate the layer-by-layer (LbL) growth of the HKUST-1 MOF as a function of temperature and reactant concentration using a coarse-grained model that permits detailed insights into the growth mechanism. This model helps to understand the morphological features of HKUST-1 grown under different conditions and can be used to predict and optimize the temperature for the purpose of controlling the crystal quality and yield. It was found that reactant concentration affects the mass deposition rate, while its effect on the crystallinity of the generated HKUST-1 film is less pronounced. In addition, the effect of temperature on the surface roughness of the film can be divided into three regimes. Temperatures in the range from 10 to 129 °C allow better control of surface roughness and film thickness, while film growth in the range of 129 to 182 °C is characterized by a lower mass deposition rate per cycle and rougher surfaces. Finally, for T larger than 182 °C, the film grows slower, but in a smooth fashion. Furthermore, the potential effect of temperature on the crystallinity of LbL-grown HKUST-1 was quantified. To obtain high crystallinity, the operating temperature should preferably not exceed 57 °C, with an optimum around 28 °C, which agrees with experimental observations.

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Direct Layer-by-Layer Growth of Crystalline Ag-TCNQ Thin Films on Functionalized Au Substrate: How Critical Is the pH of Ag(I) Solution?

The Journal of Physical Chemistry Letters ◽

10.1021/acs.jpclett.0c03229 ◽

2020 ◽

Vol 11 (24) ◽

pp. 10548-10551

Author(s):

Aswani Sathish Lathika ◽

Shammi Rana ◽

Anupam Prasoon ◽

Pooja Sindhu ◽

Debashree Roy ◽

...

Keyword(s):

Thin Films ◽

Layer Growth ◽

Layer By Layer

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Narrow growth window for stoichiometric, layer-by-layer growth of LaAlO3 thin films using pulsed laser deposition

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2016.03.025 ◽

2016 ◽

Vol 443 ◽

pp. 50-53 ◽

Cited By ~ 2

Author(s):

M. Golalikhani ◽

Q.Y. Lei ◽

M.A. Wolak ◽

B.A. Davidson ◽

X.X. Xi

Keyword(s):

Thin Films ◽

Pulsed Laser Deposition ◽

Pulsed Laser ◽

Layer Growth ◽

Laser Deposition ◽

Layer By Layer

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Fabrication of [Cu2(bdc)2(bpy)]n thin films using coordination modulation-assisted layer-by-layer growth

CrystEngComm ◽

10.1039/c7ce02031g ◽

2018 ◽

Vol 20 (11) ◽

pp. 1546-1552 ◽

Cited By ~ 3

Author(s):

Ruhollah Khajavian ◽

Kamal Ghani

Keyword(s):

Thin Films ◽

Layer Growth ◽

Modulation Method ◽

Layer By Layer

We take the advantage of the layer-by-layer process to adapt it to the coordination modulation method to fabricate highly oriented [Cu2(bdc)2(bpy)]n films.

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Layer-by-Layer Growth Control of Metal–Organic Framework Thin Films Assembled on Polymer Films

ACS Applied Materials & Interfaces ◽

10.1021/acsami.0c13016 ◽

2020 ◽

Vol 12 (45) ◽

pp. 50784-50792

Author(s):

Hiroaki Ohara ◽

Shunsuke Yamamoto ◽

Daiki Kuzuhara ◽

Tomoyuki Koganezawa ◽

Hidetoshi Oikawa ◽

...

Keyword(s):

Thin Films ◽

Polymer Films ◽

Metal Organic Framework ◽

Growth Control ◽

Layer Growth ◽

Layer By Layer ◽

Metal Organic ◽

Organic Framework

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Atomic Layer and Unit-Cell Layer Growth of (Ca,Sr)CuO2 and Bi2Sr2Can-1CunO2n+4 Thin Films by Laser Molecular Bean Epitaxy

MRS Proceedings ◽

10.1557/proc-222-309 ◽

1991 ◽

Vol 222 ◽

Author(s):

Masaki Kanai ◽

Tomoji Kawai ◽

Takuya Matsumoto ◽

Shichio Kawai

Keyword(s):

Thin Films ◽

Diffraction Pattern ◽

Cell Layer ◽

Atomic Layer ◽

High Energy ◽

Layer Growth ◽

Unit Cell ◽

Layer By Layer ◽

Diffraction Intensity

ABSTRACTThin films of (Ca,Sr)CuO2 and Bi2Sr2Can-1CunO2n+4 are formed by laser molecular beam epitaxy with in-situ reflection high energy electron diffraction observation. The diffraction pattern shows that these materials are formed with layer-by-layer growth. The change of the diffraction intensity as well as the analysis of the total diffraction pattern makes It possible to control the grown of the atomic layer or the unit-cell layer.

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Electrostatic Design of Polar Metal–Organic Framework Thin Films

Nanomaterials ◽

10.3390/nano10122420 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2420

Author(s):

Giulia Nascimbeni ◽

Christof Wöll ◽

Egbert Zojer

Keyword(s):

Thin Films ◽

Electrostatic Potential ◽

Energy Gap ◽

Dipole Moments ◽

Metal Organic Framework ◽

Solid Substrate ◽

Layer Growth ◽

Layer By Layer ◽

Metal Organic ◽

Linker Molecules

In recent years, optical and electronic properties of metal–organic frameworks (MOFs) have increasingly shifted into the focus of interest of the scientific community. Here, we discuss a strategy for conveniently tuning these properties through electrostatic design. More specifically, based on quantum-mechanical simulations, we suggest an approach for creating a gradient of the electrostatic potential within a MOF thin film, exploiting collective electrostatic effects. With a suitable orientation of polar apical linkers, the resulting non-centrosymmetric packing results in an energy staircase of the frontier electronic states reminiscent of the situation in a pin-photodiode. The observed one dimensional gradient of the electrostatic potential causes a closure of the global energy gap and also shifts core-level energies by an amount equaling the size of the original band gap. The realization of such assemblies could be based on so-called pillared layer MOFs fabricated in an oriented fashion on a solid substrate employing layer by layer growth techniques. In this context, the simulations provide guidelines regarding the design of the polar apical linker molecules that would allow the realization of MOF thin films with the (vast majority of the) molecular dipole moments pointing in the same direction.

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Rheed Intensity Oscillation During Layer-by-Layer Growth of Bi-Sr-Ca-Cu-O Thin Films

MRS Proceedings ◽

10.1557/proc-275-461 ◽

1992 ◽

Vol 275 ◽

Author(s):

K. Yoshikawa ◽

N. Sasaki

Keyword(s):

Thin Films ◽

Buffer Layer ◽

High Energy ◽

Layer Growth ◽

Layer By Layer ◽

Two Dimensional ◽

Growth Interruption ◽

Layer Deposition ◽

Unit Cells ◽

Layered Growth

ABSTRACTUsing in-situ reflection high-energy electron diffraction (RHEED), we studied the growth of Bi-Sr-Ca-Cu-O (BSCCO) thin films prepared by reactive evaporation using layer-by-layer deposition. Bi2Sr2CaCu2Ox(2212) tends to be grown three-dimensionally if it is grown directly on (100) SrTiO3, in contrast to Bi2Sr2CuOx(2201) which is easily grown two-dimensionally on SrTiO3. Two-dimensional 2212 growth can be realized, if a buffer layer of 2201 is deposited on (100) SrTiO3 and growth interruption is utilized after SrO layer deposition. A buffer layer of only two 2201 unit cells improved the surface crystallinity of the substrate for the epitaxial growth of 2212. Growth interruption for two minutes after the 2nd SrO layer in the half unit cell is necessary to keep two-dimensional layered growth. The resulting Tc (zero) is 76 K and Jc (at 4.2 K) is 1.5 × 106 (A/cm2) with these epitaxial films.

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Growth of CaFeOX/LaFeO3 Superlattice on SrTiO3(100) Substrates

MRS Proceedings ◽

10.1557/opl.2011.245 ◽

2011 ◽

Vol 1292 ◽

Cited By ~ 3

Author(s):

Nobuyuki Iwata ◽

Mark Huijben ◽

Guus Rijnders ◽

Hiroshi Yamamoto ◽

Dave H. A. Blank

Keyword(s):

Thin Films ◽

Pulsed Laser Deposition ◽

Pulsed Laser ◽

Layer Growth ◽

Laser Deposition ◽

Growth Mode ◽

Layer By Layer ◽

X Ray Diffraction ◽

Reciprocal Space Mapping ◽

X Ray

ABSTRACTThe CaFeOX(CFO) and LaFeO3(LFO) thin films as well as superlattices were fabricated on SrTiO3(100) substrates by pulsed laser deposition (PLD) method. The tetragonal LFO film grew with layer-by-layer growth mode until approximately 40 layers. In the case of CFO, initial three layers showed layer-by-layer growth, and afterward the growth mode was transferred to two layers-by-two layers (TLTL) growth mode. The RHEED oscillation was observed until the end of the growth, approximately 50nm. Orthorhombic twin CaFeO2.5 (CFO2.5) structure was obtained. However, it is expected that the initial three CFO layers are CaFeO3 (CFO3) with the valence of Fe4+. The CFO and LFO superlattice showed a step-terraces surface, and the superlattice satellite peaks in a 2θ-θ and reciprocal space mapping (RSM) x-ray diffraction (XRD) measurements, indicating that the clear interfaces were fabricated.

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Effects of Stress on Step Energies and Surface Roughness

MRS Bulletin ◽

10.1557/s0883769400035302 ◽

1996 ◽

Vol 21 (4) ◽

pp. 27-30 ◽

Cited By ~ 15

Author(s):

Christopher Roland

Keyword(s):

Thin Films ◽

Strain Relaxation ◽

Three Dimensional ◽

Layer Growth ◽

Growth Mode ◽

Misfit Dislocations ◽

Layer By Layer ◽

Strained Layers ◽

The Subject ◽

Growth Changes

Strain relaxation in lattice-mismatched, heteroepitaxial systems is one of the classic problems in materials physics, which has gained new urgency with the increased applications of strained layers in microelectronic systems. In general both the structure and the integrity of the thin films are strongly influenced by strain. For instance it has long been known that under strain, the growth changes from an initial layer-by-layer growth mode to one with three-dimensional islanding. In the seminal works of van der Merwe, and Matthews and Blakeslee, this change in growth mode is explained in terms of the introduction of strain-relieving misfit dislocations, which appear when the film has reached some critical thickness. Recently it has become clear that this change in growth mode can take place even without the introduction of misfit dislocations. Such dislocation-free coherent islanding, or “roughening,” has been observed experimentally both in Ge/Si and in InGaAs/GaAs systems. Furthermore recent experiments show that in Ge/Si(100) systems, the thin films display a curious asymmetry with respect to the sign of the strain: Films under compression roughen by forming coherent islands while those under tension remain relatively smooth. A possible mechanism behind this strain-induced type of roughening is the subject of this article.

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