Nanostructured iridium oxide-hematite magnetic ceramic semiconductors

Mossbauer Spectroscopy Investigation of Thulium Oxide-Hematite Magnetic Ceramic Nanostructures

“…Even in light of the existing structural and behavioral information about thulium oxide, the present study on the Mӧssbauer spectra of thulium oxide doped hematite particles may still clarify much about the magnetic and nuclear properties of thulium. Already several studies have been performed in our solid state laboratory at Duquesne University which have demonstrated these properties in other rare earth metals such as ruthenium, iridium and europium [23]. Each of these studies used other methods to analyze the ball milled solids in addition to Mӧssbauer spectroscopy such as differential scanning calorimetry, thermal gravimetric analysis and/or x-ray powder diffraction to evaluate the properties of the systems in question.…”

Flaw-Containing Alumina Hollow Nanostructures Have Ultrahigh Fracture Strength To Be Incorporated into High-Efficiency GaN Light-Emitting Diodes

“…Ceramics are widely used as the core functional materials of many electronic and optical devices. With the tendency toward higher levels of integration and improvements in the performance of devices, many research groups are trying to introduce three-dimensional ceramic nanostructures to the design of electronic and optical device. − Particularly, the field of GaN light-emitting diodes (LEDs) has recently seen attempts to incorporate hollow nanostructures into LEDs to achieve high-efficiency LEDs for solid-state lighting. − In GaN-based LEDs, the different material properties of the GaN and sapphire lead to several problems such as a high defect density in the GaN, serious wafer bowing in large-area wafers, and poor light extraction in devices. − These problems can be resolved by introducing a few different types of hollow oxide nanostructures (silica, alumina, and so forth) into the interface between the GaN thin film and the sapphire substrate. ,, Moreover, well-defined hollow nanostructures embedded at the GaN/sapphire interface can help scatter light effectively to attain improved light extraction. , However, the formation of internal flaws, especially nanopores, can hardly be avoided during the fabrication or post-treatment process which would be a serious reliability issue because structural failure can occur due to the thermal stress that arises during the fabrication process. Therefore, when applying ceramic nanostructures to novel electronic and optical devices, it is essential to accurately estimate the fracture strength of nanoceramics with internal flaws, which also constitutes a fundamental scientific challenge in the field of nanomechanics.…”