Surface Microstructures of Ferroelectric SrBi2Ta2O9, BaTiO3 and Metallic SrRuO3 Epitaxial Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
Q. D. Jiang ◽  
Z. J. Huang ◽  
C. L. Chen ◽  
A. Brazdeikis ◽  
P. Jin ◽  
...  

ABSTRACTWe have made a comparative invetigation of the surface microstructures of epitaxially grown ferroelectric SrBi2Ta2O9, BaTiO3 films, and metallic SrRuO3 films, using scanning probe microscopy. Though their lattices (or pseudotetrogonal lattices) match closely with SrTiO3 (001) substrates, SPM results show very different surface microstructures. The surfaces of SrRuO3 films display atomically flat terraces of 90° oriented step edges. The size of steps is about 6 Å. The surface of BaTiO3 films deposited at various temperatures displays uniform rectangular islands. Different stages of SrBi2Ta2O9 epitaxial growth have been studied on thickness gradient films, which show clearly 2D nucleation and layer-by-layer growth, following a transition from 2D to 3D island growth. It finally develops into a surface exhibiting round hills consisting of curved terraces with size of steps ranging from 6 Å to 12.5 Å.

1997 ◽  
Vol 11 (21n22) ◽  
pp. 981-987
Author(s):  
H. Q. Yin ◽  
T. Arakawa ◽  
Y. Kaneda ◽  
T. Yoshikawa ◽  
N. Haneji ◽  
...  

La 2-x Sr x CuO 4 ultra-thin films with thickness 200 Å were fabricated by pulsed laser deposition method in oxygen ( O 2) atmosphere. The morphology of deposited films was investigated by reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM) and scanning electronic microscopy (SEM). The strong oxygen ambient pressure dependence of film morphology was observed. In high oxygen ambient pressure, the film growth is dominated by island growth mode. The results imply that the experimental conditions of oxygen ambient pressure and substrate temperature are critical for the layer-by-layer growth mode.


2008 ◽  
Vol 8 (5) ◽  
pp. 2544-2548 ◽  
Author(s):  
S. Dunn ◽  
H. C. Gardner ◽  
C. Bertoni ◽  
D. E. Gallardo ◽  
N. Gaponik ◽  
...  

The work that we have conducted shows that temperature affects the wavelength of light emitted from CdTe nanoparticle clusters that are in a suspension or deposited into thin films via a layer-by-layer process. Compared with the stock suspension, the films show an initial photoluminescent shift, of circa 6–8 nm to the red, when the particles are deposited. A shift of circa 6–8 nm is also seen when the suspensions are first heated to 85 °C from room temperature (20 °C) having been stored in a fridge at 5 °C. This shift is non-recoverable. With continual cycling from room temperature to 85 °C the suspensions show a slight tendency for the emission to move increasingly to the red; whereas the films show no such tendency. In both cases, the range in emission is ca 10 nm from the room temperature state to 80 °C. The intensity of the emission from the film drops abruptly (ca 50% reduction) after one cycle of heating; in the suspension there is an initial increase (ca 3–5% increase) in intensity before it decays. We see that the shift towards the red has been attributed to energy transfer or a rearrangement of the packing of the particles in the thin films. After conducting analysis of the films using scanning probe microscopy we have determined that a change in the morphology is responsible for the permanent shift in emission wavelength associated with prolonged heating. The influence of traps has not been ruled out, but the morphological change in the samples is very large and is likely to be the dominating mechanism affecting change for the red shift at room temperature.


1999 ◽  
Vol 574 ◽  
Author(s):  
J. Lettieri ◽  
M. A. Zurbuchen ◽  
G. W. Brown ◽  
Y. Jia ◽  
W. Tian ◽  
...  

Abstract(001)-oriented epitaxial SrBi2Nb2O9 thin films have been grown by pulsed laser deposition on (001) SrTiO3 and (001) LaAlO3—Sr2AlTaO6 substrates at optimized growth conditions. 4-circle x-ray diffraction, Rutherford backscattering spectrometry, and transmission electron microscopy reveal highly oriented epitaxial films. Atomic force microscopy indicates spiral growth for films grown on SrTiO3 and layer-by-layer growth for films grown on LaAlO3—Sr2AlTaO6.


MRS Bulletin ◽  
2004 ◽  
Vol 29 (7) ◽  
pp. 484-487 ◽  
Author(s):  
Masahiko Tomitori ◽  
Toyoko Arai

AbstractScanning tunneling microscopy and noncontact atomic force microscopy have been used to observe germanium growth on Si(001) and Si(111). The atomically resolved images provide invaluable information on heteroepitaxial film growth from the viewpoints of both industrial application and basic science. We briefly review the history of characterizing heteroepitaxial elemental semiconductor systems by means of scanning probe microscopy (SPM), where the Stranski–Krastanov growth mode can be observed on the atomic scale:the detailed phase transition from layer-by-layer growth to three-dimensional cluster growth was elucidated by the use of SPM. In addition, we comment on the potential of SPM for examining the spectroscopic aspects of heteroepitaxial film growth, through the use of SPM tips with well-defined facets.


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 ◽  
...  

2013 ◽  
Vol 1507 ◽  
Author(s):  
Ryosuke Yamauchi ◽  
Geng Tan ◽  
Daishi Shiojiri ◽  
Nobuo Tsuchimine ◽  
Koji Koyama ◽  
...  

ABSTRACTWe examined the influence of momentary annealing on the nanoscale surface morphology of NiO(111) epitaxial thin films deposited on atomically stepped sapphire (0001) substrates at room temperature in O2 at 1.3 × 10−3 and 1.3 × 10−6 Pa using a pulsed laser deposition (PLD) technique. The NiO films have atomically flat surfaces (RMS roughness: approximately 0.1–0.2 nm) reflecting the step-and-terrace structures of the substrates, regardless of the O2 deposition pressure. After rapid thermal annealing (RTA) of the NiO(111) epitaxial film deposited at 1.3 × 10−3 Pa O2, a periodic straight nanogroove array related to the atomic steps of the substrate was formed on the film surface for 60 s. In contrast, the fabrication of a transient state in the nanogroove array formation was achieved with RTA of less than 1 s. However, when the O2 atmosphere during PLD was 1.3 × 10−6 Pa, random crystal growth was observed and resulted in a disordered rough surface nanostructure after RTA.


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