Alkali titanates including the Andesson-Wadsley type A$_\text{2}$OยทnTiO$_\text{2}$ (A = alkali) and the lepidocrocite-type A$_\text{x}$M$_\text{y}$Ti$_\text{2-y}$O$_\text{4}$ are diverse in crystal structure, composition, and microstructure including microcrystals or nanotubes. They are composed of tunnels or sheets of corrugated, double edge-shared (Ti,M)O$_\text{6}$ with varying lengths of...
We investigated the effects of external pressure on the superfluid density of s-wave isotropic superconductors by the BCS theory and semi-classical approach. The analytic results obtained the equation of superfluid density with pressure variables involved were derived. After that, the derived equations were numerically calculated in used to predict the experimental results in the superfluid...
In this study, we used a two-band Ginzburg-Landau technique to investigate the surface critical magnetic field (Hc3) of magnetic superconductors, with the first band being anisotropic superconductors and the second band being isotropic superconductors. Following the calculation of the 1st Ginzburg-Landau equation, a surface critical magnetic field and its temperature dependent surface critical...
The chromium aluminium nitride (CrAlN) thin films were deposited on Si by using reactive DC unbalanced magnetron sputtering method from alloy target and then annealed in air at different temperatures for 1 hr. The effect of annealing temperature on the structure, chemical composition, morphology, and hardness of the films was characterized by XRD, EDS, FE-SEM, and Nanoindentation,...
In this talk, I will present my ongoing research on the theme of bacterial cellulose nanocomposites. Bacterial cellulose (BC) is a natural polymer with a three-dimensional network of nanofibers. It is produced by cultivation of certain types of bacteria strain. The structure and properties of BC are very unique. It exhibits remarkable mechanical properties, porosity, water absorbency,...
Titanium nitride (TiN) thin films were deposited on Si substrates by reactive DC unbalanced magnetron sputtering from metallic Ti targets. The effect of N2 flow rate, in the range of 1.0โ4.0 sccm with 1 sccm increment, on the structure of the as-deposited TiN films was investigated. The crystal structures were identified by the GI-XRD technique. The thicknesses, microstructures, and surface...
Organic-inorganic hybrid perovskites are currently some of the most promising photovoltaic materials to produce highly efficient and cost-effective solar cells. Currently, many approaches have been proposed to prepare high-quality perovskite layers. The antisolvent technique is an effective and widely used method that can be done by dropping antisolvent into the rotating precursor surface...
$Zn^2+/Nb^5+$ co-doped $TiO_2$ (ZNTO) nanocrystalline powders were prepared by a combustion process. A pure rutile-$TiO_2$ phase of powders and sintered ceramics with a dense microstructure was achieved. Both co-dopants were homogeneously dispersed in the ceramic microstructure. The presence of oxygen vacancies was confirmed by Raman techniques. The thermally activated giant-dielectric...
Due to their high potential for use in ceramic capacitors, highโperformance giant dielectric properties (HPโGDPs), i.e., high dielectric constant (ษสน), low loss tangent (tan$\delta$), and the temperature stability of ษสน over a wide temperature range (ฮษสน/ษสน$_{25}$(%)) < $\pm 15$, of acceptor/donor (A/D) codopedโ$TiO_{2}$ ceramics have been widely studied since the discovery of a...
Research in van der Waals heterostructures has been rapidly progressing in the past decade, thanks to the art of sequential and deterministic placement of one two-dimensional (2D) material over another. The successful creation of heterostructures however has relied largely on expensive transfer systems that are not easily accessible to researchers. Although a few reports on low-cost systems...
Excellent giant dielectric properties (ExGDPs) of dielectric oxides have been widely investigated due to their significant potential for many applications, especially for ceramic capacitors. However, low loss tangent (tan$\delta$) and temperature coefficient ($\Delta$$\varepsilon$$^,$(T)/$\varepsilon$$^,$$_\text{RT}$) are difficult to achieve. In this presentation, we show systematic...
An abruptness of InGaAs/InP heterointerfaces in the superlattice (SL) structure grown by metal-organic vapor-phase epitaxy has been improved by optimizing a gas-purging period of tertiary-butyl phosphine (TBP) onto the InGaAs terminated surface, and tertiary-butyl arsenide (TBA) onto the InP terminated surface. The non-abrupt heterointerface is a result of intermixing layer formation caused by...
EFFECT OF ANNEALING CONDITIONS ON VO2 THIN FILMS PREPARED BY SOL-GEL METHOD
Sub.Lt.Pongsatorn Panburana, Salinporn Kittiwatanakul
Abstract
Vanadium Dioxide has attracted considerable attention because of the metal-semiconductor phase transition at 68oC. This reversible transition changes crystal structure from monoclinic to rutile resulting in tremendously change of transmittance and...
Nowadays, the most anxious problem is global warming which caused by an emission of CO2. To solve this problem, this research proposes the use of high porosity, stability, and simple synthesized material, metal-organic framework (MOFs). The aim of this work are synthesis and chemical modification of MOFs, UiO-66(Zr) that prepared from plastic waste, polyethylene terephthalate (PET)....
The bulk $Cr_2O_3$ (Chromia) is one of the candidates for voltage-controlled spintronics which is a key element for magnetoelectric random access memory (MERAM) due to its antiferromagnetic and magnetoelectric effects in high temperature. However, engineering applications MERAM require thin films to reduce the voltage required and the chromia films might have different physical and magnetic...
The recent experimental and theoretical search for near-room temperature superconductors
have shed light of interest on metal hydride as the critical temperature can vary from a
few kelvins to over 200 kelvins. One problem occurring in the theoretical research of the
material is that the traditional way of studying thermal superconductivity material is through
calculation of...
Vanadium pentoxide (V2O5) is one of the promising cathode materials for Mg-ion batteries owing to its high capacity, safety, and low toxicity. However, it still suffers from sluggish charge transport kinetics and low stability. To overcome these problems, experiments reported that using aqueous electrolytes dramatically improves ion diffusion and capacity of V2O5-based cathode. Proton from...
Over the last decade since the discovery of graphene, two-dimensional materials have gained a great attention due to their outstanding properties suitable for fabrication of next generation nanodevices. A single-layered diamond or diamane, whose high stiffness and high thermal conductivity are inherited from its bulk counterpart, is a candidate for heat dissipating device applications....
Transition-metal carbides/nitrides (MXenes) and their alloys, the largest family of two-dimensional materials, are gaining a lot of attention in the material research community due to their high potential in many applications, e.g., batteries, supercapacitors, electromagnetic and interference shielding. In this work, we investigated the thermodynamic stability of...
This work presents fabrication and characterization of a p-n junction in Si. The p-n junction was fabricated simply by thermal diffusion of n-type Si wafer with boron deposited on the surface. The depth of the p-n junction was primarily predicted by the Fickโs law of diffusion. Boron deposition was carried out in a vacuum system using an electron beam evaporator. The deposited samples were...
The outbreak of COVID-19 affects a daily life of human beings so protective equipment such as surgical masks is become essential. In this research, the development of filter layers for surgical masks from poly butylene saccinate (PBS) fiber nanocomposite which is a biodegrable polymer and copper nanoparticle (Cu NPs) that can inhibit microorganisms and can be synthesized from organic...
Giant dielectric (GD) ceramics have been extensively reported in recent years due to their potential for use in highโperformance capacitors. However, the strong temperature stability of high dielectric permittivity ($ฮตห > 10^3$) and low dielectric loss tangent (tanฮด < 0.05) have been difficult to accomplish. In this work, a novel GD oxide was discovered in (Tb+Nb) coโdoped $TiO_2$ (TNTO)...
