High Root Mean Square Roughness Research Articles

Facile fabrication of Mxene coated metal mesh-based material for oil /water emulsion separation

The present study was set out to synthesize Mxene (Ti3C2Tx) and functionalized Mxene nanoparticles and fabricating Mxene coated stainless steel meshes using the dip-coating methodology to investigate the capability of Mxene nanoparticles in oil-water emulsion separation. O/W mixtures separation with extraordinary 100% of effectiveness and purity using designed grid was observed. Most specifically, Mxene fabricated mesh showed good resistance to corrosive solutions of HCl and NaOH and was used to separate O/W at harsh medium condition with a separation efficiency of more than after 96.0% replicated experiment, and its super-hydrophilicity persisted in spite of the air exposure condition, extreme fluids immersion, or abrasion. The XRD, FTIR, SEM, FESEM, AFM and DLS tests have been performed to characterize the Mxene coating and its effectiveness on the O/W separation. These analyzes confirm the fabricated tough super-hydrophilic stainless-steel mesh explored in this research can basically be utilized as a highly effective useful mesh for O/W fluid separation under different sever circumstances. The XRD pattern of the resulting powder shows a single phase formation of Mxene, the SEM and FESEM images confirms creation of coated mesh with approximately 30 µ pore size, AFM tests verify that structures (both in nm and µm sizes) formation with high RMS (Root Mean Square) roughness values of 0.18 µm and 0.22 µm for Mxene and carboxylic-Mxene coated mesh. The DLS tests prove the droplets size distribution of emulsion has been augmented after several O/W separation, which confirmed the coagulating mechanism of oil droplets once contacting with the Mxene and carboxylic Mxene coatings of the mesh.

High Haze Ratio-Based ITO Films Prepared on Periodic Textured Glass Surfaces for Thin Film Solar Cells

Light-trapping phenomenon is limited due to non-uniform surface structure of transparent conducting oxide (TCO) films. The proper control of surface structure with uniform cauliflower TCO films may be appropriate for efficient light trapping. We report a light-trapping scheme of SF6/Ar plasma-based textured glass surfaces for high root-mean-square (RMS) roughness and haze ratio of ITO films. It was observed that the variation in Ar flow ratio in SF6/Ar plasma during the inductive coupled plasma-reactive ion etching (ICP-RIE) process was an important factor to improve the haze ratio of textured glass. The SF6/Ar plasma textured glass showed low etching rates due to the presence of various metal elements, such as Al, B, F, and Na. The ITO films were deposited on SF6/Ar plasma-textured glass substrates showed the high RMS roughness (433 nm) and haze ratio (67.8%) in the visible wavelength region. The change in surface structure has a negligible influence on the electrical properties of ITO films. The TCO films deposited on periodic textured glass surfaces with high RMS roughness and haze ratio are proposed for high-efficiency amorphous silicon (a-Si) thin-film solar cells.

Reducing Adhesion Force by Means of Atomic Layer Deposition of ZnO Films with Nanoscale Surface Roughness

Adhesion is a big concern for the design of Si-based microelectromechanical devices. A ZnO film with nanoscale surface roughness is a promising candidate to decrease adhesion as the protective coating. In this study, the adhesion force of ZnO films prepared by atomic layer deposition (ALD) on a Si (100) substrate was studied. The root-mean-square (RMS) roughness of the ZnO films was in the range of 0.7-4.28 nm, and the contact angle of water was in the range of 85-88°. The adhesion force was measured by atomic force microscopy (AFM) at both low (12%) and high (60%) relative humidities. The results show that the adhesion force decreases as the surface roughness increases. A low adhesion force at high RMS roughness is attributed to the large asperities on the film, and a large adhesion force at high humidity is attributed to the large capillary force. The experimental adhesion force was compared to the force calculated using the Rabinovich model. Although the theoretical value underestimates the experimental value, the proportion of the two components of the adhesion force is clearly shown. At the low humidity, the van der Waals force component differs not greatly with the capillary force component, while at the high humidity, the capillary force component becomes dominant.

EFFECTS OF ARGON+ ION BOMBARDMENT ON A PLATINUM/ZIRCONIUM DIOXIDE/IRIDIUM RESISTIVE SWITCHING MEMORY CELL

We have fabricated Pt/ZrO2/Ir memory cells with pristine and Ar+ ion bombarded ZrO2 films, which show unipolar resistive switching behaviors. Ar+ ion bombardment induces change in surface morphology and chemical states of ZrO2 films. We have found that forming voltage significantly decreases in a Pt/ZrO2/Ir memory cell whose Ar+ ion bombarded ZrO2 film shows oxygen vacancy like defects and the largest root-mean-square (RMS) roughness. It seems that forming process may be more easily induced in an Ar+ ion bombarded ZrO2 film with higher RMS roughness mainly due to locally enhanced electric field in a region with oxygen vacancy like defects.

Investigation of distributed Bragg reflector growth conditions for high‐brightness AlGaInP light‐emitting diodes

Abstract— The effect of growth conditions of a distributed Bragg reflector (DBR) structure on the performance of AlGaInP light‐emitting diodes (LEDs) have been investigated. Increasing the growth temperature and the flow rate of AsH3 as well as lowering the growth pressure resulted in improved reflectivity and root‐mean‐square (RMS) roughness of the high‐aluminum‐content multiple pairs of the DBR structure. An increase in the growth temperature may improve the mobility of atoms on the surface for the positioning of the right atomic site and to reduce oxygen incorporation. An increase in the flow rate of AsH3 can suppress the arsenic vacancy formation at higher V/III ratios. Furthermore, reduction in growth pressure can suppress the convection flow on the epitaxial growth surface. To verify the influence of DBR growth conditions on the successive growth of LED structures, the growth of full LED structures having two different DBR growth conditions was performed, and AlGaInP red LEDs using full LED structures were fabricated. It was found that higher growth temperature and AsH3 flow rate with lower growth pressure for the DBR structure produced improved output power of the AlGaInP LEDs, which can be attributed to the high reflectivity and low RMS roughness of the DBR structure.

Adhesion and contact modeling and experiments in microelectromechanical systems including roughness effects

The intermolecular adhesive forces in microelectromechanical systems (MEMS) applications are very significant and can hinder normal operation of sensors and actuators as well as micro-engines where catastrophic adhesion and high friction could be promoted. It has been experimentally shown that surface texturing (roughening) decreases the effect of these forces. In this paper, a model that predicts the effects of roughness, on the adhesion and contact forces in MEMS interfaces is presented. The three key parameters used to characterize the roughness, the asymmetry and the flatness of a surface topography are the root-mean-square roughness (RMS), skewness and kurtosis, respectively. It is predicted that surfaces with high RMS, high kurtosis and positive skewness exhibit lower adhesion and are thus less prone to collapsing when they come into contact or near contact. Moreover, polysilicon films with different levels of roughness, asymmetry and peakiness (sharpness) were fabricated. Experiments were conducted to evaluate the adhesive pull-off forces associated with these films. The roughness characteristics of these films were also used in the model to predict the adhesive pull-off forces. Good agreement was obtained between the theoretical and experimental results. Such a model could be used to determine the critical characteristics of a microstructure prior to fabrication to prevent adhesion and lower friction in terms of surface roughness, mechanical properties and environment.