Characterization of pulsed laser deposited MoS2 by transmission electron microscopy

1993 ◽  
Vol 8 (11) ◽  
pp. 2933-2941 ◽  
Author(s):  
S.D. Walek ◽  
M.S. Donley ◽  
J.S. Zabinski ◽  
V.J. Dyhouse

Molybdenum disulfide is a technologically important solid phase lubricant for vacuum and aerospace applications. Pulsed laser deposition of MoS2 is a novel method for producing fully dense, stoichiometric thin films and is a promising technique for controlling the crystallographic orientation of the films. Transmission electron microscopy (TEM) of self-supporting thin films and cross-sectional TEM samples was used to study the crystallography and microstructure of pulsed laser deposited films of MoS2. Films deposited at room temperature were found to be amorphous. Films deposited at 300 °C were nanocrystalline and had the basal planes oriented predominately parallel to the substrate within the first 12–15 nm of the substrate with an abrupt upturn into a perpendicular (edge) orientation farther from the substrate. Spherically shaped particles incorporated in the films from the PLD process were found to be single crystalline, randomly oriented, and less than about 0.1 μm in diameter. A few of these particles, observed in cross section, had flattened bottoms, indicating that they were molten when they arrived at the surface of the growing film. Analytical electron microscopy (AEM) was used to study the chemistry of the films. The x-ray microanalysis results showed that the films have the stoichiometry of cleaved single crystal MoS2 standards.

1997 ◽  
Vol 493 ◽  
Author(s):  
J. C. Jiang ◽  
X. Pan ◽  
C. L. Chen

ABSTRACTThe structural characteristics of SrRuO3 thin films deposited on a (001) SrTiO3 substrate by pulsed laser were studied by transmission electron microscopy (TEM) and high-resolution TEM. TEM studies of cross-sectional specimens revealed the epitaxial growth of the films with the SrRuO3-(110) plane parallel to the SrTiO3-(001) plane. Two types of 90° rotational domain structures were observed in both cross-sectional and plan-viewing specimens. The in-plane orientations of these domains with respect to the substrate are either of SrRuO3-[110] // SrTiO3 - [100] and SrRuO3-[001] // SrTiO3-[010], or of SrRuO3-[110] // SrTiO3-[010] and SrRuO3-[001] // SrTiO3-[100].


2009 ◽  
Vol 65 (6) ◽  
pp. 694-698 ◽  
Author(s):  
Y. Han ◽  
I. M. Reaney ◽  
D. S. Tinberg ◽  
S. Trolier-McKinstry

SrRuO3 (SRO) thin films grown on (001)p (p = pseudocubic) oriented LaAlO3 (LAO) by pulsed laser deposition have been characterized using transmission electron microscopy. Observations along the 〈100〉p directions suggests that although the SRO layer maintains a pseudocube-to-pseudocube orientation relationship with the underlying LAO substrate, it has a ferroelastic domain structure associated with a transformation on cooling to room temperature to an orthorhombic Pbnm phase (a − a − c + Glazer tilt system). In addition, extra diffraction spots located at ±1/6(ooo)p and ±1/3(ooo)p (where `o' indicates an index with an odd number) positions were obtained in 〈110〉p zone-axis diffraction patterns. These were attributed to the existence of high-density twins on {111}p pseudocubic planes within the SrRuO3 films rather than to more conventional mechanisms for the generation of superstructure reflections.


2001 ◽  
Vol 16 (8) ◽  
pp. 2336-2342 ◽  
Author(s):  
A. M. Serventi ◽  
M. A. El Khakani ◽  
R. G. Saint-Jacques ◽  
D. G. Rickerby

Highly conductive iridium dioxide (IrO2) thin films have been deposited onto in situ oxidized Si(100) substrates by means of a reactive pulsed laser deposition (PLD) process. The polycrystalline IrO2 films were obtained by ablating a metal iridium target under an optimal oxygen background pressure of 200 mtorr and at different substrate deposition temperatures (Td ) ranging from 350 to 550 °C. Conventional and high-resolution transmission electron microscopy (HRTEM) techniques were used to investigate the micro- and nanostructural changes of the PLD IrO2 films as a function of their deposition temperatures. The microstructure and the morphology of the PLD IrO2 films was found to change drastically from an irregular and loosely packed columnar structure at Td = 300 °C to a uniform and densely packed columnar structure for higher Td (≥350 °C). For IrO2 films deposited in the 350 ≤ Td ≤ 550 °C range, HRTEM have revealed the presence of highly textured arrangements of almost spherical IrO2 nanograins (of 3–5 nm diameter, regardless of Td) in the columns (of which diameter was found to increase from 85 ± 15 to 180 ± 20 nm as Td increases from 350 to 550 °C). Lattice resolution and dark-field imaging have pointed out the presence of large IrO2 crystallites made of many similarly oriented nanograins (i.e., under the same Bragg diffraction conditions). Moreover, a high continuity of the lattice planes across the entire crystallite was clearly observed. This latter aspect together with the highly textured nanostructure of the IrO2 films correlate well with their high conductivity (42 ± 6 μω cm for Td ≥ 400), which was found to be comparable with that of bulk single-crystal IrO2.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3645
Author(s):  
Liyao Zhang ◽  
Yuxin Song ◽  
Nils von den Driesch ◽  
Zhenpu Zhang ◽  
Dan Buca ◽  
...  

The structural properties of GeSn thin films with different Sn concentrations and thicknesses grown on Ge (001) by molecular beam epitaxy (MBE) and on Ge-buffered Si (001) wafers by chemical vapor deposition (CVD) were analyzed through high resolution X-ray diffraction and cross-sectional transmission electron microscopy. Two-dimensional reciprocal space maps around the asymmetric (224) reflection were collected by X-ray diffraction for both the whole structures and the GeSn epilayers. The broadenings of the features of the GeSn epilayers with different relaxations in the ω direction, along the ω-2θ direction and parallel to the surface were investigated. The dislocations were identified by transmission electron microscopy. Threading dislocations were found in MBE grown GeSn layers, but not in the CVD grown ones. The point defects and dislocations were two possible reasons for the poor optical properties in the GeSn alloys grown by MBE.


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