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, ...

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...

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...

We report on the growth and characterization of high-quality GaN nanowires for hydrogen sensors. We grew the GaN nanowires by catalytic chemical vapor deposition (CVD) using gold thin films as a catalyst on a Si wafer with an insulating SiO2 layer. Structural characterization of the as-grown nanowires by several methods shows that the nanowires are single-crystal wurtzite GaN. Photoluminescence...

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...

Gallium nitride (GaN) is an III-V semiconductor with a direct band-gap of 3.4 eV. GaN has important potentials in white light-emitting diodes, blue lasers, and field effect transistors because of its super thermal stability and excellent optical properties, playing main roles in future lighting to reduce energy cost and sensors to resist radiations. GaN nanomaterials inherit bulk properties of ...

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...

The optimization of the epitaxial quality and ordering of coaxial GaN/InGaN/GaN nanoheterostructures is the main focus of this study. Two approaches for the realization of upright ZnO nanipillars, used as templates for the epitaxially grown GaN layers, with their respective degrees of pattern arrangement are introduced. Consequently, the growth of coaxial GaN/InGaN/GaN quantum wells (for three ...

We report on a demonstration of GaN digital circuits implemented in a first generation GaN digital technology, which has yielded circuits of considerable complexity. We have implemented simple logic blocks, comparators, ring-oscillators and frequency dividers. We have yielded a 31-stage ring-oscillator using 217 transistors [1]. As a result of unique material characteristics GaN digital control...