Search results for "Engineering physics"
showing 10 items of 182 documents
Numerical modelling of the industrial silicon single crystal growth processes
2007
Silicon wafers produced from the silicon single crystals are the basic material for the manufacturing of various kinds of electronic devices determining the everyday life of the modern society. Silicon single crystals industrially are mainly grown by two methods - by the Czochralski and by the floating zone technique. Both of them involve various physical processes with complex interactions which makes the experimental optimization of the growth techniques a rather hard and expensive task. Therefore, mathematical modelling supported by the rapid increase of the computer power has become an effective means in the development of the industrial crystal growth. (© 2007 WILEY-VCH Verlag GmbH & C…
Photoelectric fields in doped lithium niobate crystals
2019
Photoinduced light scattering (PILS) in nominally pure stoichiometric and congruent lithium niobate single crystals (LiNbO3), and ones doped with B³⁺, Cu²⁺, Zn²⁺, Mg²⁺, Gd³⁺, Y³⁺, Er³⁺ cations was studied. All crystals have a relatively low effect of photorefraction and are promising materials for frequency conversion, electro-optical modulators and shutters. It was found that the photovoltaic and diffusion fields for some crystals have a maximum at a wavelength of 514.5 nm. All the crystals studied are characterized by a maximum of the integral intensity of the speckle structure of the PILS at a wavelength of 514.5 nm.
Recent developments in the manipulation of magnetic domain walls in CoFeB–MgO wires for applications to high-density nonvolatile memories
2015
Abstract The recent discovery that magnetic domain walls can be moved under a small current without any magnetic field opens a perspective for a paradigm shift in mass storage design. However, several fundamental questions must be answered before the technology can be considered feasible. This review covers the current understanding of domain wall (DW) propagation in CoFeB–MgO structures with perpendicular magnetic anisotropy. These films exhibit a very low density of pinning centers and can be integrated in Magnetic Tunnel Junctions, making them very promising for manipulating multiple domain walls in ultra-high-density spintronic devices. Several important issues are addressed: the physic…
Semitransparent Perovskite Solar Cells for Building Integration and Tandem Photovoltaics: Design Strategies and Challenges
2021
Over the past decade, halide perovskite systems have captured widespread attention among researchers since their exceptional photovoltaic (PV) performance was disclosed. The unique combination of optoelectronic properties and solution processability shown by these materials has enabled perovskite solar cells (PSCs) to reach efficiencies higher than 25% at low fabrication costs. Moreover, PSCs display enormous potential for modern unconventional PV applications, since they can be made lightweight, semitransparent (ST), and/or flexible by means of appropriate design strategies. In particular, by enabling transparency and high efficiency simultaneously, ST-PSCs hold great promise for future ve…
Assessing Radiation Hardness of SIC MOS Structures
2018
It is widely known that devices based on wide gap semiconductors show potential benefits in terms of saving mass, increasing power densities compared with standard Silicon ones [1]. The higher operating temperatures these components can withstand can also reduce the power budget currently used for cooling down power electronics. These factors are critical in space applications where, for example SiC devices are very promising. However, in this field reliability is a paramount requirement, and radiation conditions can compromise the usage of these new technologies.
Raman signal reveals the rhombohedral crystallographic structure in ultra-thin layers of bismuth thermally evaporated on amorphous substrate
2021
Under the challenge of growing a single bilayer of Bi oriented in the (111) crystallographic direction over amorphous substrates, we have studied different thicknesses of Bi thermally evaporated onto silicon oxide in order to shed light on the dominant atomic structures and their oxidation. We have employed atomic force microscope, X-ray diffraction, and scanning electron microscope approaches to demonstrate that Bi is crystalline and oriented in the (111) direction for thicknesses over 20 nm. Surprisingly, Raman spectroscopy indicates that the rhombohedral structure is preserved even for ultra-thin layers of Bi, down to $\sim 5$ nm. Moreover, the signals also reveal that bismuth films expo…
Modeling propagation in high-power microwave devices
1999
Toward Metal Halide Perovskite Nonlinear Photonics.
2018
The possibility of controlling light using the nonlinear optical properties of photonic devices opens new points of view in information and communications technology applications. In this Perspective, we review and analyze the potential role of metal halide perovskites in a framework different from their usual one in photovoltaic and light-emitting devices, namely, the one where they can play as nonlinear photonic materials. We contextualize this new role by comparing the few extant results on their nonlinear optical properties to those of other known nonlinear materials. As a result of this analysis, we provide a vision of future developments in photonics that can be expected from this new…
Failure Estimates for SiC Power MOSFETs in Space Electronics
2018
Silicon carbide (SiC) power metal-oxide-semiconductor field effect transistors (MOSFETs) are space-ready in terms of typical reliability measures. However, single event burnout (SEB) due to heavy-ion irradiation often occurs at voltages 50% or lower than specified breakdown. Failure rates in space are estimated for burnout of 1200 V devices based on the experimental data for burnout and the expected heavy-ion linear energy transfer (LET) spectrum in space. peerReviewed