J Nanosci Nanotechnol
February 2019
The effects of Al metal pre-deposition under different conditions on GaN grown on Si(111) substrates by metal-organic chemical vapor deposition (MOCVD) have been investigated. Al pre-deposition improves surface morphology and crystal quality of GaN grown on Si. The surface morphology of Al pre-deposition layer, AlN, and GaN vary depending on Al pre-deposition temperature.
View Article and Find Full Text PDFBackground: The α2 adrenergic agonist dexmedetomidine (DEX) has huge potential for protecting against cerebral vasospasm, a leading cause of death and disability after subarachnoid hemorrhage (SAH). Biomarker assays for SAH have recently emerged as tools for predicting vasospasm and outcomes. We investigated the effects of DEX on vasospasm and assessed relevant biomarkers in a rat SAH model.
View Article and Find Full Text PDFUrine output is closely associated with renal function and has been used as a diagnostic criterion for acute kidney injury (AKI). However, urine output during cardiopulmonary bypass (CPB) has never been identified as a predictor of postoperative AKI. Considering altered renal homeostasis during CPB, we made a comprehensible approach to CPB urine output and evaluated its predictability for AKI.
View Article and Find Full Text PDFWe demonstrated the InGaN/GaN-based light-emitting diodes (LEDs) with SiO₂ nanoparticles embedded in nanopillar GaN template. With the SiO₂ nanoparticles placed between the GaN nanopillars, subsequent overgrowth of GaN layer started only on the exposed tips of the nanopillars and rapidly switched to the lateral growth mode. This resulted in a high quality GaN layer "sitting" on the nanopillars and the layer of pores formed over the SiO₂ nanoparticles.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2014
Free-standing GaN light-emitting diode (LED) structure with high crystalline quality was fabricated by combining electrochemical and photoelectrochemical etching followed by regrowth of LED structure and subsequent mechanical detachment from a substrate. The structural quality and composition of the regrown LED film thus produced was similar to standard LED, but the photoluminescence and electroluminescence intensity of the LED structures on the etched template were several times higher than for standard LED. The performance enhancement was attributable to additional light scattering and improved crystalline quality as a result of the combined etching scheme.
View Article and Find Full Text PDFIn this study, we have fabricated 375-nm-wavelength InGaN/AlInGaN nanopillar light emitting diodes (LED) structures on c-plane sapphire. A uniform and highly vertical nanopillar structure was fabricated using self-organized Ni/SiO2 nano-size mask by dry etching method. To minimize the dry etching damage, the samples were subjected to high temperature annealing with subsequent chemical passivation in KOH solution.
View Article and Find Full Text PDF2.7 times increase in room temperature photoluminescence (PL) intensity and 3.2 times increase in electroluminescence (EL) intensity were observed in blue multi-quantum-well (MQW) GaN/InGaN light emitting diodes (LEDs) as a result of introduction of nano-needle structure embedded with Ag nanoparticles (NPs) into n-GaN film underlying the active MQW region and thick p-GaN contact layer of LEDs.
View Article and Find Full Text PDFOptical properties of InGaN/GaN multi-quantum-well (MQW) structures with a nanolayer of Ag/SiO2 nanoparticle (NP) on top were studied. Modeling and optical absorption (OA) measurements prove that the NPs form localized surface plasmons (LSP) structure with a broad OA band peaked near 440-460 nm and the fringe electric field extending down to about 10 nm into the GaN layer. The presence of this NP LSP electrical field increases the photoluminescence (PL) intensity of the MQW structure by about 70% and markedly decreases the time-resolved PL (TRPL) relaxation time due to the strong coupling of MQW emission to the LSP mode.
View Article and Find Full Text PDFJ Nanosci Nanotechnol
November 2007
InGaN/GaN multiple quantum wells (MQWs) were successfully grown on the inclined GaN(1101) microfacets. Conventional photolithography and subsequent growth of GaN were employed to generate the V-shaped microfacets along (1120) direction. The well-developed microfacets observed by scanning electron microscopy and the clear transmission electron microscope interfacial images indicated that the MQW was successfully grown on the GaN microfacets.
View Article and Find Full Text PDFThe effects of sulfur addition on the formation of conjugated linoleic acid (CLA) isomers were studied during the hydrogenation of soybean oil with a nonselective type nickel catalyst. Sulfur addition greatly promoted CLA formation in soybean oil during hydrogenation. As the amount of sulfur increased to a certain level, the maximal quantity of CLA in soybean oil during hydrogenation increased greatly.
View Article and Find Full Text PDF