The Effect of Hydrogen on the Structure of Amorphous and Microcrystalline Sic Prepared by the Polymer Route

1989 ◽  
Vol 164 ◽  
Author(s):  
C-J Chu ◽  
S-J. Ting ◽  
F. Bobonneau ◽  
J.D. Mackenzie

AbstractAmorphous SiC:H thin films have been deposited on different substrates using metal-organic polymer solutions. The structure of the amorphous phase has been proposed as the rings of Si and C atoms with various sizes. Microcrystalline phase can be produced when fired at temperatures higher than 1000°C. 13C MAS-NMR shows the evidence of the C=C-double bonds. ESR results show the major defects in this material are C-dangling bonds. As predict, defects can be decreased by heat treatment in H2 atmosphere.

2019 ◽  
Vol 962 ◽  
pp. 17-21 ◽  
Author(s):  
Hiromi Kobori ◽  
Tohru Kitamura ◽  
Toshifumi Taniguchi ◽  
Tetsuo Shimizu

We have studied the strong hole self-doping into LaMnO3(LMO) thin films produced by metal organic decomposition (MOD) method. With different heat treatment conditions, LMO thin films have been prepared by the MOD method in the 100 % O2gas atmosphere. We consider that the excess of O2-ions in LMO thin films induces the strong hole self-doping into LMO ones. The quantity of excess O2-ions in LMO is sensitive to the heat treatment conditions of the LMO production, especially the temperature, time and atmosphere gas. Although LMO single crystal is an antiferromagnetic insulator, LMO thin films we have produced in the 100 % O2gas atmosphere by use of the MOD method shows the properties of ferromagnetic metal.


2020 ◽  
Vol 853 ◽  
pp. 63-67
Author(s):  
Hiromi Kobori ◽  
Thoru Kitamura ◽  
A. Yamasaki ◽  
T. Taniguchi ◽  
T. Shimizu

We have studied the magneto-transport properties in LMO thin films on a-SiO2 substrates produced by the metal organic decomposition (MOD) method. LMO thin films have been prepared by the MOD method in the 100 % O2 gas atmosphere on different heat treatment conditions. Although LMO single crystal is an antiferromagnetic insulator, LMO thin films we have produced in the 100 % O2 gas atmosphere by use of the MOD method shows the ferromagnetic metal properties for suitable heat treatment conditions. We consider that the excess of O2- ions in LMO thin films produced in the 100 % O2 gas atmosphere induces the strong hole self-doping into those and changes to ferromagnetic metal. The quantity of excess O2- ions in LMO is sensitive to the heat treatment conditions of the LMO production, especially the temperature, time and atmosphere gas. We have obtained the coercive forces from the magnetic field dependence of magnetoresistance. Based on the temperature dependence of the coercive forces, we have estimated the Curie temperature of LMO thin films.


Author(s):  
R. M. Anderson

Aluminum-copper-silicon thin films have been considered as an interconnection metallurgy for integrated circuit applications. Various schemes have been proposed to incorporate small percent-ages of silicon into films that typically contain two to five percent copper. We undertook a study of the total effect of silicon on the aluminum copper film as revealed by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and ion microprobe techniques as a function of the various deposition methods.X-ray investigations noted a change in solid solution concentration as a function of Si content before and after heat-treatment. The amount of solid solution in the Al increased with heat-treatment for films with ≥2% silicon and decreased for films <2% silicon.


1996 ◽  
Vol 444 ◽  
Author(s):  
Hyeon-Seag Kim ◽  
D. L. Polla ◽  
S. A. Campbell

AbstractThe electrical reliability properties of PZT (54/46) thin films have been measured for the purpose of integrating this material with silicon-based microelectromechanical systems. Ferroelectric thin films of PZT were prepared by metal organic decomposition. The charge trapping and degradation properties of these thin films were studied through device characteristics such as hysteresis loop, leakage current, fatigue, dielectric constant, capacitancevoltage, and loss factor measurements. Several unique experimental results have been found. Different degradation processes were verified through fatigue (bipolar stress), low and high charge injection (unipolar stress), and high field stressing (unipolar stress).


Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1552 ◽  
Author(s):  
Weber ◽  
Graniel ◽  
Balme ◽  
Miele ◽  
Bechelany

Improving the selectivity of gas sensors is crucial for their further development. One effective route to enhance this key property of sensors is the use of selective nanomembrane materials. This work aims to present how metal-organic frameworks (MOFs) and thin films prepared by atomic layer deposition (ALD) can be applied as nanomembranes to separate different gases, and hence improve the selectivity of gas sensing devices. First, the fundamentals of the mechanisms and configuration of gas sensors will be given. A selected list of studies will then be presented to illustrate how MOFs and ALD materials can be implemented as nanomembranes and how they can be implemented to improve the operational performance of gas sensing devices. This review comprehensively shows the benefits of these novel selective nanomaterials and opens prospects for the sensing community.


1992 ◽  
Vol 7 (11) ◽  
pp. 3065-3071 ◽  
Author(s):  
Peir-Yung Chu ◽  
Isabelle Campion ◽  
Relva C. Buchanan

Phase transformation and preferred orientation in ZrO2 thin films, deposited on Si(111) and Si(100) substrates, and prepared by heat treatment from carboxylate solution precursors were investigated. The deposited films were amorphous below 450 °C, transforming gradually to the tetragonal and monoclinic phases on heating. The monoclinic phase developed from the tetragonal phase displacively, and exhibited a strong (111) preferred orientation at temperature as low as 550 °C. The degree of preferred orientation and the tetragonal-to-monoclinic phase transformation were controlled by heating rate, soak temperature, and time. Interfacial diffusion into the film from the Si substrate was negligible at 700 °C and became significant only at 900 °C, but for films thicker than 0.5 μm, overall preferred orientation exceeded 90%.


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.


Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1348
Author(s):  
Hiroki Nagai ◽  
Naoki Ogawa ◽  
Mitsunobu Sato

Deep-ultraviolet (DUV) light-transparent conductive composite thin films, consisting of dispersed multiwalled carbon nanotubes (MWCNTs) and SiO2 matrix composites, were fabricated on a quartz glass substrate. Transparent and well-adhered amorphous thin films, with a thickness of 220 nm, were obtained by weak ultraviolet (UV) irradiation (4 mW cm−2 at 254 nm) for more than 6 h at 20−40 °C onto the precursor films, which were obtained by spin coating with a mixed solution of MWCNT in water and Si(IV) complex in ethanol. The electrical resistivity of MWCNT/SiO2 composite thin film is 0.7 Ω·cm, and transmittance in the wavelength region from DUV to visible light is higher than 80%. The MWCNT/SiO2 composite thin film showed scratch resistance at pencil hardness of 8H. Importantly, the resistivity of the MWCNT/SiO2 composite thin film was maintained at the original level even after heat treatment at 500 °C for 1 h. It was observed that the heat treatment of the composite thin film improved durability against both aqueous solutions involving a strong acid (HCl) and a strong base (NaOH).


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