The Study of Surface Morphology and Roughness of Silicon Wafers Treated by Plasma

Plasma is generally used for the doping of semiconductors. During plasma doping process, plasma interacts with the surface of semiconductor. As a result, defects are induced in the surface region. In this work, the surface morphology and roughness of silicon wafer caused by plasma treatment is studied by use of atom force microscope (AFM). It is found that, during the plasma process, each of the processing time of plasma, location of silicon wafer in plasma and the way of placement of silicon wafer has an influence on the surface morphology and roughness and the reason is discussed. The interaction between plasma and the surface of silicon wafer is qualitatively discussed.

Noise minimised high resolution digital holographic microscopy applied to surface topography

The topography of surface relief gratings was studied by digital holographic microscopy. The applicability of the method for quantitative measurements of surface microstructure at nanoscale was demonstrated. The method for wavefront reconstruction of surface relief from a digital hologram recorded in off-axis configuration was also applied. The main feature is noise filtration due to the presence of noise in the recorded intensity distribution and the use of all orders of the hologram. Reconstruction results proved a better effectiveness of our approach for topography studying of relief grating patterned on a ChG As2S3 – Se nanomultilayers in comparison with standard Fourier Transform and Atom Force Microscope methods.

Physical Properties of MEH-PPV Thin Films at Different Ageing

Poly (2-methoxy-5(2’-ethylhexyloxy)-phenylene vinylene) (MEH-PPV) thin films were deposited by spin-coating technique. The MEH-PPV powders were dissolved in toluene solution. In this study, we report the effect of ageing on electrical and optical properties MEH-PPV thin films. The thickness of MEH-PPV increased as ageing time increased. The electrical properties were obtained using 2-point probe. The resistivity of thin films decreased as ageing time increased and vice versa with conductivity. The optical properties were investigated using UV-Visible-NIR (UV-VIS-NIR) and atom force microscope (AFM). From UV-Vis result shows the lower band gaps of films in toluene solution proved MEH-PPV has longer conjugation segments. The surface roughness of thin films decreased with the increased of ageing time; which is caused by the aggregation of the MEH-PPV. The PL spectra show the quenching of emission might be due to the conjugation of length polymer changes in different ageing times.

Construction of Nano Coenzyme and Enzyme Multilayer Film on Gold Electrode by Self-Assembly Method

A ferrocene labeled high molecular weight coenzyme derivative (PEI-Fc-NAD) was prepared by attaching both ferrocene (Fc) and coenzyme (nicotinamide adenine dinucleotide, NAD+) to the backbone of poly (ethylenimine) (PEI). A NAD-dependent glucose-6-phosphate dehydrogenase (G6PDH) was used with PEI-Fc-NAD to fabricate a multilayer film on gold electrode by layer-by-layer self-assembly method. The G6PDH/PEI-Fc-NAD multilayer film was characterized by atom force microscope and electrochemical experiment, which proved that a nanostructure thin film was immobilized by the LBL technique. The modified electrode showed the current response to glucose-6-phosphate in the absence of free coenzyme, and kept about 85% response after storage in buffer for 2 month.

Effect of Orientation of Reinforcements on the Quality of the Machined Surface in Machining Aluminium Composites

The precision turning experiments of aluminium composites reinforced with SiC whisker reinforcements were done by polycrystalloid diamond (PCD) tools. The measure analysis of the machined surface was carried out with Atom Force Microscope (AFM) and Scan Electronic Microscope (SEM). The roughness values of the machined surface were measured by Talysurf-6. The results show that the orientation of reinforcements in the machined surface will directly affect the deformation mechanism of SiC whiskers, microstructures of the machined surface, and to determine the quality of the machined surface. In the five types from A to E of SiC whisker orientation, the orientation of case A easily makes to produce SiC whisker deformation by cutting off directly, and to result in the best machined surface. However, for the orientation of case E, it easily makes to induce SiC whisker deformation by pulling out or pressing into aluminium matrix, and to produce the worst machined surface.

Asymmetry-Induced Supramolecular Helices of Pyrene-Perylene Bisimide Triads

The formation of helical nanostructure is investigated for donor/acceptor system. The helices of the supramolecular nanofibres can be revealed by atom force microscope (AFM) and circular dichroism (CD) measurement. The expermental results show the Py-Per-Py can self assembly into helical nanofibres. The controlled experiments on the compound Py-e-Per-e-Py with symmetrical conformation indicates the formation of helical nanofibres may be attributed to asymmetrical conformation.

Influence of Laser Radiation on Optical Properties and Surface Structure of CdZnTe Crystal

The change of surface of Cd0.9Zn0.1Te crystal morphology after irradiation by pulsed Nd:YAG laser has been studied. Thermogradient effect (TGE) has the main role in the interaction process of laser radiation with semiconductors. A change of the irradiated surface relief has been observed by atom force microscope. Self-organizing nano-cones are observed on the irradiated surface of Cd0.9Zn0.1Te crystal at intensity of the laser in the range of 4.0 – 12.0 MW/cm2. A graded band gap structure with optical window was formed at the top of nano-cones.

Surface Modification of Wool Fibers by Ecologically Ozone-Assisted Treatment

Wool fiber was modified using ecologically acceptable ozone-assisted treatment (ECO) in this study. Chemical and mechanical analysis of the treated samples compared with the untreated and Basolan○,R88 treated ones are reported. An atom force microscope (AFM) results show that the crimple was generated on the surface of ECO treated wool fiber and the peak-to-valley decreased slightly. However, Fourier transforms infrared spectra (FTIR) results suggest the absorbency and the oxidation of disulfide bonds increased after the ECO treatment, especially at 1024cm-1. The crystallinity of the treated wool fiber slightly increased based on the X-ray results. The treatment also led to reduction in strength of the wool fiber.

Determination of Particle Size Distribution of Nano-TiO2 Coating Film by AFM and Image Analysis

Nano-TiO2 coating film is one of the efficient photocatalysts. The particle size distribution of TiO2 has important influence on photocatalytic activity. A new method to determine the particle size distribution of TiO2 nano-film coated on ceramic was developed, by which the images of film acquired by Atom force microscope (AFM) were processed, and TiO2 particles contacted with others were separated and detected. The particle size distributions of two TiO2 nano-films were determined.