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Article
Transport characteristics of AlGaN/GaN structures for amplification of terahertz radiations
The study of devices to amplify the terahertz (THz) radiations is a subject of intense research among the scientific community owing to its interdisciplinary applications. We explore the possibility of amplifi...
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Article
Influence of the Mg precursor on the incorporation of Mg in MOVPE grown GaN.
Incorporation of Mg in metalorganic vapour phase epitaxy (MOVPE) GaN has been investigated, using two different Mg precursors: bis-methylcyclopentadienyl magnesium [(MeCp)2Mg] and Solution bis-cyclopentadienyl ma...
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Article
Micro Epitaxial lateral overgrowth of GaN/sapphire by Metal Organic Vapour Phase Epitaxy
GaN/sapphire layers have been grown by Metal Organic Vapour Phase Epitaxy (MOVPE). An amorphous silicon nitride layer is deposited using a SiH4/NH3 mixture prior to the growth of the low temperature GaN buffer la...
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Article
Photoluminescence excitation spectroscopy of GaN thin layers as a function of temperature
We report on photoluminescence and photoluminescence excitation experiments performed on hexagonal GaN layers grown on a Sapphire substrate. Information about extrinsic and intrinsic optical properties have be...
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Article
p-do** of GaN by MOVPE
Mg has been widely used as p-do** species despite its intrinsic difficulties. It is nowadays well established that during the growth process of Mg doped GaN, atomic H is generated from the decomposition of NH3 ...
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Article
Yellow luminescence in Mg-doped GaN
Optical thresholds, that correspond to a level located at 1 eV above the valence band, are observed by photocapacitance techniques in n-type Mg-doped GaN. In undoped GaN, this level has been previously related...
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Article
XPS study of Au/GaN and Pt/GaN contacts
Au/GaN and Pt/GaN contacts have been studied with XPS. According to XPS depth profiling, the N signal is weak in the region below the metal contact and the Pt or Au signal decreases much more slowly than expec...
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Article
Exciton dynamics in thick GaN MOVPE epilayers deposited on sapphire.
Time-resolved photoluminescence spectra have been recorded on three GaN epitaxial layers of thickness 2.5 µm, 7 µm and 16 µm, at various temperatures ranging from 8K to 300K. The layers were deposited by MOVPE...
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Article
Characterization and Modeling of Photoconductive GaN Ultraviolet Detectors
In this work high gain GaN photoconductive UV detectors have been fabricated and characterized, and a novel gain mechanism, dominant in these detectors, is described. DC responsivities higher than 103A/W have bee...
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Article
Temperature behaviour of the yellow emission in GaN
Even in good quality undoped GaN samples, as assessed by the intense excitonic emission, the yellow band is present. This band has been attributed either to a shallow donor to deep double donor pair recombinat...
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Article
A Tem study of GaN Grown by ELO on (0001) 6H-SiC
The misfit between GaN and 6H-SiC is 3.5% instead of 16% with sapphire, the epitaxial layers have similar densities of defects on both substrates. Moreover, the lattice mismatch between AlN and 6H-SiC is only ...
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Article
Metal/GaN contacts studied by electron spectroscopies
Au/GaN and Cu/GaN Schottky contacts have been studied using X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Clean and stoechiometric GaN samples were obtained using in situ hydrog...
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Article
Electrical Characterization of Sputter Deposition Induced Defects in n-GaN
We have used current-voltage (I-V) measurements to assess and compare the electrical characteristics of resistively evaporated and sputter deposited Au Schottky contacts on epitaxially grown GaN. These I-V measur...
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Article
Electrical Characterization of Defects Introduced in n-GaN During High Energy Proton and He-Ion Irradiation
We report on the electrical properties of defects as determined by deep level transient spectroscopy (DLTS) introduced in epitaxially grown n-GaN by 2.0 MeV protons and 5.4 MeV He-ions. After He-ion bombardmen...
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Article
Raman Map** and Finite Element Analysis of Epitaxial Lateral Overgrown GaN on Sapphire Substrates
Using micro-Raman scattering and finite element (FE) analysis, stress fields in epitaxial lateral overgrown (ELO) GaN fabricated by metalorganic vapor phase epitaxy (MOVPE) on sapphire substrates using a two-s...
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Article
Photoluminescence between 3.36 eV and 3.41 eV from GaN Epitaxial Layers
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Chapter and Conference Paper
Low Dislocations Density GaN/Sapphire for Optoelectronic Devices
It is nowadays well established that threading dislocations (TDs) are degrading the performances and the operating lifetime of optoelectronic GaN-based devices (LDs and UV-LEDs). GaN/sapphire layers have been ...
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Article
Electric-field-induced impact ionization of excitons in GaN and GaN/AlGaN quantum wells
Impact ionization of exciton states in epitaxial GaN films and GaN/AlGaN quantum-well structures was studied. The study was done using an optical method based on the observation of exciton photoluminescence qu...
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Article
Defects Created by 25 keV Hydrogen Implantation in n-type GaN
We have studied defects introduced in n-GaN during 25 keV hydrogen and 40 keV He implantation using deep level transient spectroscopy (DLTS). These measurements revealed that 25 keV hydrogen implantation introduc...
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Article
Optically detected magnetic resonance study of defects in undoped, Be-doped, and Mg-doped GaN
Undoped, Be-doped, and Mg-doped GaN samples were investigated with photoluminescence-detected electron paramagnetic resonance (PL-EPR) and electron-nuclear double resonance (PL-ENDOR). Two types of shallow don...
