Search results for " Semiconductor"
showing 10 items of 332 documents
Solvothermal synthesis derived Co-Ga codoped ZnO diluted magnetic degenerated semiconductor nanocrystals
2018
Authors kindly acknowledge to the Estonian Research Council ( PUT1096 , IUT2-25 , PUT735 ), the Estonian Centre of Excellence in Research project “Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics (TK141), and the financial support of HZB. We are grateful to the staff of BESSY II for the assistance and co-operation during the synchrotron-based measurements.
Long-Living Light-Emitting Electrochemical Cells - Control through Supramolecular Interactions
2008
Light-emitting electrochemical cells with lifetimes surpassing 3000 hours at an average luminance of 200 cd m(-2) are obtained with an ionic iridium(III) complex conveniently designed to form a supramolecularly caged structure.
In-situ study of multi-phase indium nanoparticle growth on/into CuPcF4 organic thin film in ultra-high vacuum conditions
2021
Abstract We study the in-situ growth of a nanocomposite material consisting of a thin CuPcF4 film and multiphase/multidimensional indium nanoparticles, self-organizing on the surface and in the bulk, at various stages of thermal deposition of metal on an organic film under ultrahigh vacuum conditions. The analysis of high-resolution transmission electron microscopy (HR-TEM) images provided valuable information about the evolution of morphology, size, density, and distribution of indium nanoparticles upon indium deposition. These 2D/3D ultra-small nano-objects turned out to have not only body-centered tetragonal (bct) crystal structure, typical for bulk indium, but also unusual face-centered…
Structural and chemical analysis of annealed plasma-enhanced atomic layer deposition aluminum nitride films
2016
Plasma-enhanced atomic layer deposition was utilized to grow aluminum nitride (AlN) films on Si from trimethylaluminum and N2:H2 plasma at 200 °C. Thermal treatments were then applied on the films which caused changes in their chemical composition and nanostructure. These changes were observed to manifest in the refractive indices and densities of the films. The AlN films were identified to contain light element impurities, namely, H, C, and excess N due to nonideal precursor reactions. Oxygen contamination was also identified in the films. Many of the embedded impurities became volatile in the elevated annealing temperatures. Most notably, high amounts of H were observed to desorb from the…
Resonance assisted jump-in voltage reduction for electrostatically actuated nanobeam-based gateless NEM switches.
2019
Electrostatically actuated nanobeam-based electromechanical switches have shown promise for versatile novel applications, such as low power devices. However, their widespread use is restricted due to poor reliability resulting from high jump-in voltages. This article reports a new method for lowering the jump-in voltage by inducing mechanical oscillations in the active element during the switching ON process, reducing the jump-in voltage by more than three times. Ge0.91Sn0.09 alloy and Bi2Se3 nanowire-based nanoelectromechanical switches were constructed in situ to demonstrate the operation principles and advantages of the proposed method.
Investigation of the Impact of Neutron Irradiation on SiC Power MOSFETs Lifetime by Reliability Tests
2021
High temperature reverse-bias (HTRB), High temperature gate-bias (HTGB) tests and electrical DC characterization were performed on planar-SiC power MOSFETs which survived to accelerated neutron irradiation tests carried out at ChipIr-ISIS (Didcot, UK) facility, with terrestrial neutrons. The neutron test campaigns on the SiC power MOSFETs (manufactered by ST) were conducted on the same wafer lot devices by STMicroelectronics and Airbus, with different neutron tester systems. HTGB and HTRB tests, which characterise gate-oxide integrity and junction robustness, show no difference between the non irradiated devices and those which survived to the neutron irradiation tests, with neutron fluence…
Advances in solution-processed near-infrared light-emitting diodes
2021
A summary of recent advances in the near-infrared light-emitting diodes that are fabricated by solution-processed means, with coverage of devices based on organic semiconductors, halide perovskites and colloidal quantum dots.
High-Pressure Softening of the Out-of-Plane A2u(Transverse-Optic) Mode of Hexagonal Boron Nitride Induced by Dynamical Buckling
2019
We investigate the highly anisotropic behavior of the in-plane and out-of-plane infrared-active phonons of hexagonal boron nitride by means of infrared reflectivity and absorption measurements under high pressure. Infrared reflectivity spectra at normal incidence on high-quality single crystals show strict fulfillment of selection rules and an unusually long E1u[transverse-optic (TO)] phonon lifetime. Accurate values of the dielectric constants at ambient pressure ϵ0= 6.96, ϵ∞= 4.95, ϵ 0= 3.37, and ϵ∞ = 2.84 have been determined from fits to the reflectivity spectra. The out-of-plane A2u phonon reflectivity band is revealed in measurements on an inclined facet, and absorption measurements a…
Heteropolyacid-Based Heterogeneous Photocatalysts for Environmental Application
2015
Polyoxometalates (POMs) are a wide class of discrete nanosized transition metal–oxygen clusters. The synthesis of POMs has received great interest not only because they present intriguing architectures but also because they have potential applications in catalysis, medicine, electrochemistry, materials design or models for self-assembling nanoscale systems. Recently, POMs have also been studied as green and cheap photocatalysts. The potentialities of POMs are attributed to their unique structural features; indeed, POMs are photostable and non-toxic, have oxygen-rich surfaces and excellent redox properties and possess photochemical characteristics similar to those of the semiconductor photoc…
Defect spectroscopy of single ZnO microwires
2014
The point defects of single ZnO microwires grown by carbothermal reduction were studied by microphotoluminescence, photoresistance excitation spectra, and resistance as a function of the temperature. We found the deep level defect density profile along the microwire showing that the concentration of defects decreases from the base to the tip of the microwires and this effect correlates with a band gap narrowing. The results show a characteristic deep defect levels inside the gap at 0.88 eV from the top of the VB. The resistance as a function of the temperature shows defect levels next to the bottom of the CB at 110 meV and a mean defect concentration of 4 1018 cm3 . This combination of tech…