We propose in this work, contact Schottky Nickel/porous silicon (PSi) system, coupled to nanocrystallites size variation of material for a possible technique to reduce dark current. The device consists of metal- semiconductor-metal photodiode (MSM-PD). Higher barrier Φ Β enhances the performance of MSM-PD through reduction in dark current (Is), and benefits to resolve noise from signal detection of the devices. In order to reduce much more Is, we proposed different anodization times (5–7–10 min) as method to tune the size of nanocrystallites. As result Is value was reduced to almost two orders of magnitude for 10 min etching time, and the value of Is ≈ 10–10 A. Φ Β reached the value of 0.882 eV. Among the hypothesis suggested in the reduction of Is was the quantum confinement effects. According to Rhoderick model, the Schottky barrier height is explicitly linked to the band gap energy due to the presence of interface states. The existence of narrow nanocrystallites increased energy band gap of PSi and the Schottky barrier height, which in turn reduces Is. The photoluminescence measurements confirmed our hypothesis. Photosensitivity of the device was established by adopting the MSM configuration, and strong absorption was detected in visible range.

Journal of Nano- and Electronic Physics. Scientific journal. ISSN: 2077-6772. Journal abbreviation: J. Nano- Electron. Phys. No page charges. All articles are freely available on-line. Issued 4 times per year. Publisher: Sumy State University. (Sumy, Ukraine)

PbTi_1−xFe_xO_3−δ (x = 0, 0.3, 0.5, and 0.7) ceramics were prepared using the classical solid-state reaction method. The investigated system presented properties that were derived from composition, microstructure, and oxygen deficiency. The phase investigations indicated that all of the samples were well crystallized, and the formation of a cubic structure with small traces of impurities was promoted, in addition to a tetragonal structure, as Fe³⁺ concentration increased. The scanning electron microscopy (SEM) images for PbTi_1−xFe_xO_3−δ ceramics revealed microstructures that were inhomogeneous with an intergranular porosity. The dielectric permittivity increased systematically with Fe³⁺ concentration, increasing up to x = 0.7. A complex impedance analysis revealed the presence of multiple semicircles in the spectra, demonstrating a local electrical inhomogeneity due the different microstructures and amounts of oxygen vacancies distributed within the sample. The increase of the substitution with Fe³⁺ ions onto Ti⁴⁺ sites led to the improvement of the magnetic properties due to the gradual increase in the interactions between Fe³⁺ ions, which were mediated by the presence of oxygen vacancies. The PbTi_1−xFe_xO_3−δ became a multifunctional system with reasonable dielectric, piezoelectric, and magnetic characteristics, making it suitable for application in magnetoelectric devices.

Bismuth ferrite (BiFeO₃, abbreviated as BFO) has great potential for environmental applications

Our objective is to present a valuable contribution towards designing more efficient sensors using undoped ZnO nanofils. The utilization of nanostructures based on ZnO has led to significant enhancements in sensor performance, due to the excellent chemical and thermal stability exhibited at its high melting temperature, our work, we focused on modeling the behavior of ZnO semiconductors by employing the Schottky defect model as a source of free carriers. Specifically, we examined the theoretical model of oxygen molecule adsorption and desorption. We explored two types of molecules responsible for adsorbing reducing gases, taking acetone gas as an example. Through the use of the COMSOL software, we found that the interaction between the solid and gas occurs at a considerably lower temperature of 295 °C, compared to ZnO thin films, which typically require temperatures as high as 500 °C. This outcome can be attributed to the behavior of ZnO nanostructures, where the influence of side surfaces (1010) is predominant, along with their lower activation energy compared to (0002) surfaces. These ZnO nanofils exhibit numerous active and thermodynamically favorable surfaces, which facilitate the adsorption of reducing gases. Employing simulation methods, such as COMSOL, offers an effective approach for achieving an optimal device design, thereby ensuring superior device performance. This research demonstrates the potential of using undoped ZnO nanofils for the development of highly efficient sensors with enhanced operational characteristics.