P-type conducting layers are critical in GaN-based devices such as LEDs and laser diodes. Such layers are often produced by doping GaN with Mg, but the hole concentration can be enhanced using AlGaN/GaN p-type superlattices by exploiting the built-in polarisation fields. A Mg-doped AlGaN/GaN superlattice was studied using SIMS. Although the AlGaN and GaN were nominally doped to the same level, ...

Giant axonal neuropathy (GAN) is a rare disease caused by mutations in the GAN gene, which encodes gigaxonin, an E3 ligase adapter that targets intermediate filament (IF) proteins for degradation in numerous cell types, including neurons and fibroblasts. The cellular hallmark of GAN pathology is the formation of large aggregates and bundles of IFs. In this study, we show that both the distribut...

In this study, we used metal organic chemical vapor deposition to form gallium nitride (GaN) epilayers on c- and a-axis sapphire substrates and then used the nanoscratch technique and atomic force microscopy (AFM) to determine the nanotribological behavior and deformation characteristics of the GaN epilayers, respectively. The AFM morphological studies revealed that pile-up phenomena occurred o...

Double heterostructures of strained GaN quantum wells (QWs) sandwiched between relaxed AlN layers provide a platform to investigate the quantum-confined electronic and optical properties of the wells. The growth of AlN/GaN/AlN heterostructures with varying GaN quantum well thicknesses on AlN by plasma molecular beam epitaxy (MBE) is reported. Photoluminescence spectra provide the optical signat...

Gallium nitride (GaN) nanopowder used as a blue fluorescent material was synthesized by using a direct current (DC) non-transferred arc plasma. Gallium nitrate hydrate (Ga(NO₃)₃∙xH₂O) was used as a raw material and NH₃ gas was used as a nitridation source. Additionally, melamine (C₃H₆N₆) powder was injected into the plasma flame to prevent the oxidation of gallium to gallium oxide (Ga₂O₃). Argo...

Ultralow wear nature of gallium nitride (GaN) has been revealed recently. The wear rate for GaN has a significant dependence on humidity, ranging from 9 10 9 mm3/Nm to 9.5 10 7 mm3/Nm; the mechanisms responsible for this variation in wear remain unclear. Here, we performed reciprocal sliding test on GaN under different environments and characterized the chemical compositions of corresponding wo...

Two simple class-F NVI1VIIC power amplifiers are described using 0.7tm field-plated GaN HEMT devices. One circuit was designed for operation at 2.0 GHz and achieved a power-added-efficiency of 50%, 38 dBm output power, and 6.2 W/mm power density. A second circuit was designed at 2.8 GHz and achieved a PAE of 46% with 37 dBm output power and 7.0 W/mm power density.

GaN based electronic devices have progressed rapidly over the past decades and are nowadays starting to replace Si and classical III-V semiconductors in power electronics systems and high power RF amplifiers. AlGaN/GaN heterostructures have been, until recently, the materials system of choice for nitride based electronics. The limits of AlGaN/GaN technologies are now known and alternative route...

This article reports forward and reverse biased emission in vertical ZnO nanowire/p-GaN heterojunction light emitting diodes (LEDs) grown out of solution on Mg-doped p-GaN films. The electroluminescence spectra under forward and reverse bias are distinctly different. Forward bias showed two peaks centered around 390 nm and 585 nm, while reverse bias showed a single peak at 510 nm. Analysis of t...

Mutations in gigaxonin were identified in giant axonal neuropathy (GAN), an autosomal recessive disorder. To understand how disruption of gigaxonin's function leads to neurodegeneration, we ablated the gene expression in mice using traditional gene targeting approach. Progressive neurological phenotypes and pathological lesions that developed in the GAN null mice recapitulate characteristic hum...