We report the performance of extended-gate field-effect transistor (EGFET) pH sensors based on the properties of nanostructured porous silicon layer (nano PSi). Four different forms of nano PSi layers with different characteristic features are used as a sensor for determining the pH level. The synthesized nano PSi layer was prepared by laser-assisted etching of n-type (100) by using different illumination intensities 15, 30, 45 and 60 mW/cm2 of 530 nm laser wavelength. The structural and morphological properties of nano PSi were investigated through exploring scanning electron microscopy, X-ray diffraction (XRD) and gravimetrical measurements. Nano PSi with pore-like structures of various pore shapes and sizes are as follows: fine circular pores, star full pore, circular pores and rectangular pores; star full pore shape was prepared through varying the laser illumination intensity. The Fourier transform infrared spectroscopy, current–voltage measurements and specific surface area of were employed to describe the density of the hydrogenated dangling bonds (Si–Hx) of the nano PSi layer. The synthesized nano PSi pH sensors were tested and dry out in the pH range from 3 to 11 at room temperature. The performance of nano PSi pH sensors was comparatively analyzed based on the density of (Si–Hx), specific surface area, porosity and layer thickness of nano PSi. Concerning EGFET pH sensor showed noticeably enhanced pH sensitivity and linearity with increasing the density of (Si–Hx) and specific surface area. Higher sensitivity with excellent linearity was obtained for pore-like structures of circular pore shapes when the laser illumination intensity was about 45 mW/cm2.
In this work, the temperature dependence of extended X-ray absorption fine structure (EXAFS) of the body-centered cubic crystals was investigated based on the anharmonic correlated Einstein model using the classical statistical theory. The oscillation of the anharmonic EXAFS spectra presented in terms of the cumulant expansion up to the fourth order. Here, the thermodynamic parameters of a system are derived from an anharmonic effective potential that has taken into account the influence of all nearest neighbors of absorbing and backscattering atoms. Analytical expressions of the first four EXAFS cumulants are obtained in simple forms of temperature or parallel mean-square relative displacement. The numerical results for crystalline molybdenum in the temperature range from 0 to 900 K are found to be in good agreement with those obtained using the other theoretical methods and experiments at various temperatures. The analytical results for the contributions of the cumulants to the amplitude reduction and phase shift of the EXAFS oscillation discover the role and meaning of high-order cumulants in analyzing the temperature dependence of the EXAFS spectra.
In this work, the conventional chemical bath deposition (CBD) technique and its growth parameters were systematically studied to deposit CdS thin films on the glass substrate. The samples were prepared using a simple aqueous solution containing cadmium sulfate (CdSO4·8H2O), thiourea [SC(NH2)2], ammonium sulfate [(NH4)2SO4] as a source of cadmium, sulfur, and a complexing agent, respectively. The deposited films were characterized to study the surface morphology, crystallographic structure, chemical composition, optical and electrical properties. Through this study, the structure was determined to cubic with (111) preferential orientation and the crystallinity of the films was improved with the increase of film thickness. The transmission spectra were recorded in the range of wavelength 300–600 nm. The optical bandgap of the optimized CdS films was varied from 2.43 to 2.74 eV. All the films exhibit n-type of conductivity which was found in the order of 10–4 to 10–5 (1/Ω-cm), suggesting that it would be suitable for the buffer layer in thin-film solar cells.
In the present study, nematic liquid crystal (NLC) 4′-(Octyloxy)-4-biphenylcarbonitrile dispersed with three different concentrations of silver nanoparticles (Ag NPs) is characterized by electro-optical and dielectric spectroscopy method. The dispersion of Ag NPs into NLC material leads to the change in physical parameters such as dielectric permittivity, photoluminescence, threshold voltage, response time and splay elastic constant. The AC conductivity and threshold voltage of Ag NPs-dispersed composite system have increased significantly. The increase in the AC conductivity for the composite system is attributed to the Ag NPs-assisted induced charge transfer mechanism in the system. Moreover, the increase in AC conductivity value for Ag NPs/NLC composite system discloses its importance in photovoltaic solar cell.
This study was conducted to monitor the plant responses to seed priming with electromagnetic fields (0, 4, or 6 mT) or cold plasma (0, 80, or 100 s) in Salvia nemorosa . The cold plasma or electromagnetic field treatments significantly increased shoot fresh weight (49%), root fresh weight (41%), and root length (56%). The results highlighted that seed priming with cold plasma or the electromagnetic field is an effective method to modify seedling growth. The electromagnetic field and plasma treatments upregulated the AREB1 gene (mean = 3.9-fold). Except for the electromagnetic field of 4mT, the other treatments stimulated expressions of the WRKY1 gene by an average of 6.7-fold relative to the control. The cold plasma or electromagnetic field also induced the expression of cinnamoyl-CoA reductases (CCR2) gene (mean = fourfold). These treatments also changed the expression of the rosmarinic acid synthase by an average of sixfold. These findings may improve our knowledge of plant reactions to cold plasma and electromagnetic field for possible functions in seed technology.
