Unit cell layer-by-layer heteroepitaxy of BaO thin films at temperatures as low as 20 °C

1997 ◽  
Vol 15 (5) ◽  
pp. 2469-2472 ◽  
Author(s):  
T. Ohnishi ◽  
M. Yoshimoto ◽  
G. H. Lee ◽  
T. Maeda ◽  
H. Koinuma
1991 ◽  
Vol 222 ◽  
Author(s):  
Masaki Kanai ◽  
Tomoji Kawai ◽  
Takuya Matsumoto ◽  
Shichio Kawai

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.


2003 ◽  
Vol 77 (5) ◽  
pp. 619-621 ◽  
Author(s):  
D. Reisinger ◽  
B. Blass ◽  
J. Klein ◽  
J.B. Philipp ◽  
M. Schonecke ◽  
...  

2009 ◽  
Vol 614 ◽  
pp. 21-26
Author(s):  
Kenichi Tanaka ◽  
Xiao Hong Jiang

Scanning tunneling microscopy (STM) proved the existence of quasi-compounds on solid surfaces. A typical example is (-Ag-O-) or (-Cu-O-) chains grown on Ag(110) or Cu(110) surface by exposing to O2. The (-Ag-O-) chains on a Ag(110) reacts with Cu atoms to form a new quasi-compound of (-Cu-O-) chains on the Ag(110) surface. The (-Cu-O-) on the Ag(110) readily decomposes at ca. 570ºK to form Cu6 dots, and a reversible reaction of (Cu2)3 + O2. ↔ (-Cu-O-) takes place by exposing to O2. Deposited Zn, Sn and Ag atoms on a Si(111)-7x7 surface stabilize by forming Zn3, Sn2 and Sn, and Ag in a half unit cell. Layer-by-layer growth of Zn3 clusters occurs in a half unit cell, which results in the growth of a semi-conductive honeycomb layer of Zn3 clusters on the Si(111)-7x7 surface. By prohibiting hopping migration of Ag atoms on the Si(111)-7x7 surface by the adsorption of C2H5OH, nano-size Ag dots grow layer-by-layer in a limited mold spacing. The band gap of Ag-dots becomes narrower and narrower and becomes metallic at higher than 6 layers.


Author(s):  
J. T. Sizemore ◽  
D. G. Schlom ◽  
Z. J. Chen ◽  
J. N. Eckstein ◽  
I. Bozovic ◽  
...  

Investigators observe large critical currents for superconducting thin films deposited epitaxially on single crystal substrates. The orientation of these films is often characterized by specifying the unit cell axis that is perpendicular to the substrate. This omits specifying the orientation of the other unit cell axes and grain boundary angles between grains of the thin film. Misorientation between grains of YBa2Cu3O7−δ decreases the critical current, even in those films that are c axis oriented. We presume that these results are similar for bismuth based superconductors and report the epitaxial orientations and textures observed in such films.Thin films of nominally Bi2Sr2CaCu2Ox were deposited on MgO using molecular beam epitaxy (MBE). These films were in situ grown (during growth oxygen was incorporated and the films were not oxygen post-annealed) and shuttering was used to encourage c axis growth. Other papers report the details of the synthesis procedure. The films were characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM).


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1631
Author(s):  
Qiang Zhang ◽  
Yohanes Pramudya ◽  
Wolfgang Wenzel ◽  
Christof Wöll

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.


2020 ◽  
Vol 11 (24) ◽  
pp. 10548-10551
Author(s):  
Aswani Sathish Lathika ◽  
Shammi Rana ◽  
Anupam Prasoon ◽  
Pooja Sindhu ◽  
Debashree Roy ◽  
...  

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