The rapid progress in semiconductor materials and devices has promoted the development of the sensors industry. Large band gap semiconductors are ideal candidates for a variety of sensor applications. In particular, gallium nitride (GaN) is used as the sensing element for the development of chemical sensors. The recognition mechanism is based on the selective interaction of anions in solution w...

We have performed a real-time in situ x-ray scattering study of the nucleation of GaN nanowires grown by plasma-assisted molecular beam epitaxy on AlN(0001)/Si(111). The intensity variation of the GaN diffraction peak as a function of time was found to exhibit three different regimes: (i) the deposition of a wetting layer, which is followed by (ii) a supralinear regime assigned to nucleation of...

*Corresponding author email: [email protected] Abstract In the present work we report the characterization of coplanar waveguides (CPWs) implemented on AlGaN/GaN HEMT layers deposited on high-resistivity silicon (HR-Si) substrates, up to frequencies as high as 110 GHz. The topic is of interest because it is fairly widely held in the community that substrate losses could hinder the application of...

Heteroepitaxial growth of lattice mismatched materials has advanced through the epitaxy of thin coherently strained layers, the strain sharing in virtual and nanoscale substrates, and the growth of thick films with intermediate strain-relaxed buffer layers. However, the thermal mismatch is not completely resolved in highly mismatched systems such as in GaN-on-Si. Here, geometrical effects and s...

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...

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 have demonstrated a gallium nitride (GaN)-based green light-emitting diode (LED) with graphene/indium tin oxide (ITO) transparent contact. The ohmic characteristic of the p-GaN and graphene/ITO contact could be preformed by annealing at 500 °C for 5 min. The specific contact resistance of p-GaN/graphene/ITO (3.72E-3 Ω·cm²) is one order less than that of p-GaN/ITO. In addition, the 20-mA forw...

The characteristics of the reverse leakage current of GaInN/GaN multiple quantum well light-emitting diodes (LEDs) are examined with various n-type GaN doping concentrations and interpreted by using a tunnelling current model. Changing the doping concentration of the n-type GaN influences the tunnelling probability of electrons into the conduction band and thus the reverse leakage current. Redu...

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 ...

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...