Nanodynamics of Vapor-Phase Organophosphates on Silicon and OTS for MEMS Lubrication Purposes

2005 ◽  
Author(s):  
W. Neeyakorn ◽  
S. M. Lee ◽  
O. Parker ◽  
J. E. Burnette ◽  
L. S. Bilbro ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Polycrystalline Silicon ◽  
Quartz Crystal ◽  
Point Of View ◽  
Morphological Properties ◽  
Deposition Method ◽  
Mems Devices ◽  
Gold Surfaces ◽  
Force Microscopy ◽  
Atomic Force

We have performed a quartz crystal microbalance (QCM) study of the nanotribological properties of organophosphate (tricresylphosphate and t-butyl phenylphosphate) layers adsorbed from the vapor phase onto silicon (amorphous silicon and MEMS-like polysilicon), and octadecyltrichlorosilane (OTS) treated silicon and gold surfaces. The latter systems have been studied in order to explore whether organophosphates and OTS in combination might prove synergistic from a tribological point of view [1]. There is a strong possibility that this combination will also exhibit synergistic tribological behaviors when tested on actual MEMS devices. Therefore, it is important to perform QCM measurement on silicon that is as close to that of MEMS devices. In order to perform this study, we have developed a deposition method involving a Si-Ge layer that enables the growth of polycrystalline silicon on top of Cu QCM electrodes. The structural and morphological properties of these samples have been characterized with Raman spectroscopy and atomic force microscopy (AFM), confirming that they are similar in nature to the silicon in actual MEMS devices.

scholarly journals Structural and Morphological Properties of Titanium Aluminum Nitride Coatings Produced by Triode Magnetron Sputtering

2014 ◽  
Vol 10 (20) ◽  
pp. 51-64 ◽  
Author(s):  
D.M. Devia ◽  
E. Restrepo-Parra ◽  
J.M. Velez-Restrepo
Keyword(s):  
Magnetron Sputtering ◽  
Bias Voltage ◽  
Structural Changes ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Titanium Aluminum ◽  
Microscopy Techniques ◽  
Titanium Aluminum Nitride

Tix Al1−xN coatings were grown using the triode magnetron sputtering technique varying the bias voltage between -40 V and -150V. The influence of bias voltage on structural and morphological properties was analyzed by means of energy dispersive spectroscopy, x-ray diffraction and atomic force microscopy techniques. As the bias voltage increased, an increase inthe Al atomic percentage was observed competing with Ti and producing structural changes. At low Al concentrations, the film presented a FCC crystalline structure; nevertheless, as Al was increased, the structure pre-sented a mix of FCC and HCP phases. On the other hand, an increase inbias voltage produced a decrease films thickness due to an increase in colli-sions. Moreover, the grain size and roughness were also strongly influencedby bias voltage.

Fabrication of GaN Doped ZnO Nanocrystallines by Laser Ablation

2008 ◽  
Vol 8 (8) ◽  
pp. 4168-4171
Author(s):  
N. Gopalakrishnan ◽  
B. C. Shin ◽  
K. P. Bhuvana ◽  
J. Elanchezhiyan ◽  
T. Balasubramanian
Keyword(s):  
Deep Level ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Doped Zno ◽  
Krf Excimer Laser ◽  
Photoluminescence Studies

Here, we present the fabrication of pure and GaN doped ZnO nanocrystallines on Si(111) substrates by KrF excimer laser. The targets for the ablation have been prepared by conventional ceramic method. The fabricated nanocrystallines have been investigated by X-ray diffraction, photoluminescence and atomic force microscopy. The X-ray diffraction analysis shows that the crystalline size of pure ZnO is 36 nmand it is 41 nmwhile doped with 0.8 mol% of GaN due to best stoichiometry between Zn and O. Photoluminescence studies reveal that intense deep level emissions have been observed for pure ZnO and it has been suppressed for the GaN doped ZnO structures. The images of atomic force microscope show that the rms surface roughness is 27 nm for pure ZnO and the morphology is improved with decrease in rms roughness, 18 nm with fine crystallines while doped with 1 mol% GaN. The improved structural, optical and morphological properties of ZnO nanocrystalline due to GaN dopant have been discussed in detail.

scholarly journals Detection Limits of DLS and UV-Vis Spectroscopy in Characterization of Polydisperse Nanoparticles Colloids

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Emilia Tomaszewska ◽  
Katarzyna Soliwoda ◽  
Kinga Kadziola ◽  
Beata Tkacz-Szczesna ◽  
Grzegorz Celichowski ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Point Of View ◽  
Spectroscopy Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
The One

Dynamic light scattering is a method that depends on the interaction of light with particles. This method can be used for measurements of narrow particle size distributions especially in the range of 2–500 nm. Sample polydispersity can distort the results, and we could not see the real populations of particles because big particles presented in the sample can screen smaller ones. Although the theory and mathematical basics of DLS technique are already well known, little has been done to determine its limits experimentally. The size and size distribution of artificially prepared polydisperse silver nanoparticles (NPs) colloids were studied using dynamic light scattering (DLS) and ultraviolet-visible (UV-Vis) spectroscopy. Polydisperse colloids were prepared based on the mixture of chemically synthesized monodisperse colloids well characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), DLS, and UV-Vis spectroscopy. Analysis of the DLS results obtained for polydisperse colloids reveals that several percent of the volume content of bigger NPs could screen completely the presence of smaller ones. The presented results could be extremely important from nanoparticles metrology point of view and should help to understand experimental data especially for the one who works with DLS and/or UV-Vis only.

scholarly journals Physics Comes to the Aid of Medicine—Clinically-Relevant Microorganisms through the Eyes of Atomic Force Microscope

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 969
Author(s):  
Mateusz Cieśluk ◽  
Piotr Deptuła ◽  
Ewelina Piktel ◽  
Krzysztof Fiedoruk ◽  
Łukasz Suprewicz ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Antimicrobial Agents ◽  
Antimicrobial Treatment ◽  
Point Of View ◽  
Diagnostic Methods ◽  
Drug Resistant ◽  
Bacterial Strains ◽  
Force Microscopy ◽  
Atomic Force ◽  
Recent Developments

Despite the hope that was raised with the implementation of antibiotics to the treatment of infections in medical practice, the initial enthusiasm has substantially faded due to increasing drug resistance in pathogenic microorganisms. Therefore, there is a need for novel analytical and diagnostic methods in order to extend our knowledge regarding the mode of action of the conventional and novel antimicrobial agents from a perspective of single microbial cells as well as their communities growing in infected sites, i.e., biofilms. In recent years, atomic force microscopy (AFM) has been mostly used to study different aspects of the pathophysiology of noninfectious conditions with attempts to characterize morphological and rheological properties of tissues, individual mammalian cells as well as their organelles and extracellular matrix, and cells’ mechanical changes upon exposure to different stimuli. At the same time, an ever-growing number of studies have demonstrated AFM as a valuable approach in studying microorganisms in regard to changes in their morphology and nanomechanical properties, e.g., stiffness in response to antimicrobial treatment or interaction with a substrate as well as the mechanisms behind their virulence. This review summarizes recent developments and the authors’ point of view on AFM-based evaluation of microorganisms’ response to applied antimicrobial treatment within a group of selected bacteria, fungi, and viruses. The AFM potential in development of modern diagnostic and therapeutic methods for combating of infections caused by drug-resistant bacterial strains is also discussed.

scholarly journals Surface Morphology of Single and Multi-Layer Silicon Nitride Dielectric Nano-Coatings on Silicon Dioxide and Polycrystalline Silicon

2019 ◽  
Vol 26 (1) ◽  
pp. 25-29
Author(s):  
Liga AVOTINA ◽  
Elina PAJUSTE ◽  
Marina ROMANOVA ◽  
Gennady ENICHEK ◽  
Aleksandrs ZASLAVSKIS ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Surface Morphology ◽  
Polycrystalline Silicon ◽  
Chemical Vapour ◽  
Attenuated Total Reflection ◽  
Infrared Spectrometry ◽  
Chemical Bonds ◽  
Force Microscopy ◽  
Atomic Force ◽  
Pressure Chemical

Silicon nitride (Si3N4) in a form of single and multi-layer nanofilms is proposed to be used as a dielectric layer in nanocapacitors for operation in harsh environmental conditions. Characterization of surface morphology, roughness and chemical bonds of the Si3N4 coatings has an important role in production process as the surface morphology affects the contact surface with other components of the produced device. Si3N4 was synthesized by using low pressure chemical vapour deposition method and depositing single and multi-layer (3 – 5 layers) nanofilms on SiO2 and polycrystalline silicon (PolySi). The total thickness of the synthesized nanofilms was 20 – 60 nm. Surface morphology was investigated by means of scanning electron microscopy (SEM) and atomic force microscopy (AFM). Chemical bonds in the layers were identified by means of Fourier transform infrared spectrometry, attenuated total reflection (FTIR-ATR) method. (From the SEM and AFM images it was estimated that both single and multi-layer coatings are deposited homogenously. Si-N breathing and stretching modes are observed in FTIR spectra and the surface morphology is highly dependent on PolySi, therefore suggesting the decrease of the roughness of the bottom electrode for use in the nanocapacitors.

scholarly journals Early-Stage Growth Mechanism and Synthesis Conditions-Dependent Morphology of Nanocrystalline Bi Films Electrodeposited from Perchlorate Electrolyte

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1245 ◽  
Author(s):  
Daria Tishkevich ◽  
Sergey Grabchikov ◽  
Tatiana Zubar ◽  
Denis Vasin ◽  
Sergei Trukhanov ◽  
...  
Keyword(s):  
Growth Mechanism ◽  
Early Stage ◽  
Abnormal Behavior ◽  
Morphological Properties ◽  
Synthesis Conditions ◽  
Force Microscopy ◽  
Atomic Force ◽  
Galvanostatic Regime ◽  
Current Densities ◽  
Deposition Duration

Bi nanocrystalline films were formed from perchlorate electrolyte (PE) on Cu substrate via electrochemical deposition with different duration and current densities. The microstructural, morphological properties, and elemental composition were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy-dispersive X-ray microanalysis (EDX). The optimal range of current densities for Bi electrodeposition in PE using polarization measurements was demonstrated. For the first time, it was shown and explained why, with a deposition duration of 1 s, co-deposition of Pb and Bi occurs. The correlation between synthesis conditions and chemical composition and microstructure for Bi films was discussed. The analysis of the microstructure evolution revealed the changing mechanism of the films’ growth from pillar-like (for Pb-rich phase) to layered granular form (for Bi) with deposition duration rising. This abnormal behavior is explained by the appearance of a strong Bi growth texture and coalescence effects. The investigations of porosity showed that Bi films have a closely-packed microstructure. The main stages and the growth mechanism of Bi films in the galvanostatic regime in PE with a deposition duration of 1–30 s are proposed.

Imaging Electron Transport across Grain Boundaries in an Integrated Electron and Atomic Force Microscopy Platform: Application to Polycrystalline Silicon Solar Cells

2009 ◽  
Vol 1153 ◽  
Author(s):  
Manuel J Romero ◽  
Fude Liu ◽  
Oliver Kunz ◽  
Johnson Wong ◽  
Chun-Sheng Jiang ◽  
...  
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Solar Cells ◽  
Electron Transport ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
High Energy ◽  
Dominant Factor ◽  
Force Microscopy ◽  
Atomic Force

AbstractWe have investigated the local electron transport in polycrystalline silicon (pc-Si) thin-films by atomic force microscopy (AFM)-based measurements of the electron-beam-induced current (EBIC). EVA solar cells are produced at UNSW by <i>EVAporation</i> of a-Si and subsequent <i>solid-phase crystallization</i>–a potentially cost-effective approach to the production of pc-Si photovoltaics. A fundamental understanding of the electron transport in these pc-Si thin films is of prime importance to address the factors limiting the efficiency of EVA solar cells. EBIC measurements performed in combination with an AFM integrated inside an electron microscope can resolve the electron transport across individual grain boundaries. AFM-EBIC reveals that most grain boundaries present a high energy barrier to the transport of electrons for both p-type and n-type EVA thin-films. Furthermore, for p-type EVA pc-Si, in contrast with n-type, charged grain boundaries are seen. Recombination at grain boundaries seems to be the dominant factor limiting the efficiency of these pc-Si solar cells.

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