we have performed density functional theory investigations on the adsorption properties of ammonia molecule on the undoped and n-doped tio2 anatase nanoparticles. we have geometrically optimized the constructed undoped and n-doped nanoparticles in order to fully understand the adsorption behaviors of ammonia molecule. for tio2 anatase nanoparticles, the binding site is preferentially located on...

We investigate p-type GaN : Mg materials using noise spectroscopy. The epitaxial Mg-doped GaN layers were grown on a sapphire substrate by metalorganic chemical vapour deposition. Significant generation–recombination noise is observed and shown to be linked to metastable DX-like centres. We correlate these centres with metastable defects with optical ionization energies 1.1 eV and 1.9 eV, respe...

The current-voltage (I-V) characteristics of Pt/(n.u.d)-GaN and Pt/Si-doped-GaN diodes Schottky are investigated. Based on these measurements, physical mechanisms responsible for electrical conduction have been suggested. The contribution of thermionic-emission current and various other current transport mechanisms were assumed when evaluating the Schottky barrier height. Thus the generation-re...

GaN buffer deep level centers are studied coupling measurements and device physics simulations. The impact of Feand C-doped samples on low frequency device transconductance and noise is presented. The Felevel found at 0.7 eV below the GaN conduction band results in low frequency generation-recombination noise and transconductance dispersion. The agreement with the model shows that the buffer ca...

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...

This research seeks to develop a novel branch of materials systems called Distributed Intelligent Materials Systems (DIMS) which incorporate actuation, sensing, electronics and intelligence as inherent parts of the material structure. A microcantilever optical switch is fabricated as a concept demonstrator with Gallium nitride (GaN) as host material. GaN has several material characteristics whi...

Mg-doped GaN was grown by plasma-assisted molecular beam epitaxy (PAMBE) on a Fe-doped template substrate employing shutter-controlled process. The transition from n-type to p-type conductivity of in relation the N/Ga flux ratio studied. highest carrier concentration this series 3.12 × 1018 cm−3 under most N-rich condition. By modulating shutters different effusion cells for process, wide growt...

Abstract n-GaN/ AlN heterostructures were grown by molecular beam epitaxy on Si(111) substrates.The GaN films n-type doped with silicon and the effect of doping concentration structural optical properties was studied. Si promotes a reduction dislocation density as revealed x-ray data analysis Transmission Electron Microscopy. Furthermore, decrease in yellow band measured Photoluminescence Spect...