ZnO thin films with preferred orientation along the (002) plane were prepared onto the glass substrates by the sol-gel spin coating method for different post- annealing temperatures. The XRD study confirms that the thin films grown by this method have good crystalline hexagonal wurtzite structure. The optical band gap of the samples was determined from UV-visible spectra. It is found that the s...

The use of carbon nanomaterials in various applications requires precise control of their surface and bulk properties. In this paper, we present a strategy for modifying the surface chemistry, wettability, and electrical conductivity of carbon tubes and films through annealing in a vacuum. Experiments were conducted with 60-300 nm nanotubes (nanopipes), produced by noncatalytic chemical vapor d...

Cu2S thin films have been prepared by vacuum evaporation method from CuS powder. Cu2S was deposited onto precleaned flat glass substrates coated under a pressure of 10 torr at an evaporation rate of 3Å /sec. The resistivity of the vacuum evaporated Cu2S thin films was measured in the temperature range 303K-453K and was found between 10 to 10 ohm cm. This low resistivity is due to degenerate nat...

The operation of chemical vapor-deposited (CVD) graphene field-effect transistors (GFETs) is highly sensitive to environmental factors such as the substrate, polymer residues, ambient condition, and other species adsorbed on the graphene surface due to their high defect density. As a result, CVD GFETs often exhibit a large hysteresis and time-dependent instability. These problems become a major...

Metal Vapor Vacuum Arc (MEVVA) ion source (IS) is a unique tool for production of high intensity metal ion beam that can be used for material surface modification. From the other hand, the duoplasmatron ion source provides the high intensity gas ion beams. The MEVVA and duoplasmatron IS developed in Institute for Theoretical and Experimental Physics were used for the reactor steel surface modif...

This study investigated the effects of Ti content and vacuum annealing on the microstructure evolution of TixFeCoNi (x = 0, 0.5, and 1) thin films and the underlying mechanisms. The as-deposited thin film transformed from an FCC (face center cubic) structure at x = 0 into an amorphous structure at x = 1, which can be explained by determining topological instability and a hard ball model. After ...

In this work, mechanical alloying was employed to produce Ti-50Al and Ti-45Al-5Cr (at%) alloys. Alloying was performed in a planetary mill and the alloying time varying from 5 to 70h. Characterization of the powder mixture was performed by X-ray diffraction (XRD), SEM analyses and DTA test, during mechanical alloying and after annealing at 1100°c in vacuum oven. The results showed, after 50h of...

Substrate materials that are high-temperature stable are essential for sensor devices which are applied at high temperatures. Although langasite is suggested as such a material, severe O and Ga diffusion into an O-affine deposited film was observed during annealing at high temperatures under vacuum conditions, leading to a damage of the metallization as well as a change of the properties of the...

The homogeneity and luminescence properties of undoped bulk GaSb have been studied by the cathodoluminescence ~CL! technique in the scanning electron microscope. CL images have revealed a nonuniform distribution of native defects in GaSb wafers prepared from as-grown single crystals. Postgrowth annealing in vacuum, gallium, and antimony atmospheres has been performed to obtain more accurate inf...

The surface chemistry of single crystal barium titanate (BaTiO3) has been studied using temperature programmed desorption (TPD). TPD measurements were performed with several probe molecules, including methanol and carbon dioxide. The role of oxygen vacancies in the adsorption and reaction of these molecules was examined by annealing the crystal under oxidizing or reducing conditions prior to pe...