29 Result(s)
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Article
The effects of indium concentration and well-thickness on the mechanisms of radiative recombination in InxGa1−xN quantum wells
A correlation of the local indium concentration measured on an atomic scale with luminescence properties of InxGa1−xN quantum wells reveals two different types of recombination mechanisms. A piezoelectric-field b...
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Article
The influence of the sapphire substrate on the temperature dependence of the GaN bandgap
This paper analyses the influence of the sapphire substrate on stress in GaN epilayers in the temperature range between 4K and 600K. Removal of the substrate by a laser assisted liftoff technique allows, for t...
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Article
Are the Materials Properties of Indiumnitride Dominated by Defects?
Indium nitride (InN) is a promising yet technologically challenging material with a high defect density and unusual material properties. Its high electron mobility may be utilized in high power electronic devi...
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Article
Direct Electron Beam Processing Of Semiconductor Nanostructures
We used a high current density focused electron beam to modify a GaAs substrate. To avoid any oxidation or carbon contamination problem, an in-situ electron gun, combined with III-V molecular beam epitaxy (MBE...
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Article
Electrical and Optical Properties of Carbon-Doped GaN Grown by MBE on MOCVD GaN Templates Using a CCl4 Dopant Source
Carbon-doped GaN was grown by plasma-assisted molecular-beam epitaxy using carbon tetrachloride vapor as the dopant source. For moderate do** mainly acceptors were formed, yielding semi-insulating GaN. Howev...
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Article
Luminescence energy and carrier lifetime as a function of applied biaxial strain in InGaN/GaN quantum-well structures
Photoluminescence (PL) and Time-resolved PL (TR-PL) are used to measure the luminescence energy and carrier lifetime of InGaN/GaN quantum well (QW) structures as a function of biaxial strain and excitation den...
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Article
Engineering metal-impurity nanodefects for low-cost solar cells
As the demand for high-quality solar-cell feedstock exceeds supply and drives prices upwards, cheaper but dirtier alternative feedstock materials are being developed1,2,3. Successful use of these alternative feed...
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Article
Recombination Related to Two-Dimensional Electron Gas of AlxGa1−xN/GaN Single Heterostructures Studied with Picosecond Time-Resolved Photoluminescence
Nearbandgap radiative recombination in undoped AlxGa1−xN/GaN (x = 0.28 to 0.35) single heterostructures grown by metalorganic chemical vapor deposition is investigated using picosecond time-resolved photoluminesc...
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Article
P- and N-type Do** of Non-Polar A-plane GaN Grown by Molecular-Beam Epitaxy on R-plane Sapphire
Non-polar a-plane GaN films doped with Si or Mg were grown by plasma-assisted molecular-beam epitaxy on r-plane sapphire substrates. The ( $$11...
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Article
Fast Proton Damage Effects on the Luminescence Properties of High-Quality GaN
High-quality GaN layers grown by hydride-vapor phase epitaxy (HVPE) and homoepitaxial layers grown thereon by molecular beam epitaxy (MBE) are studied after fast proton irradiation. A radiation-induced decreas...
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Article
Effect of internal absorption on cathodoluminescence from GaN
We have studied optical properties of GaN grown on sapphire by metalorganic chemical vapor deposition in the near band-edge energy range by cathodoluminescence. A large shift of the bandedge luminescence to lo...
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Article
High-pressure investigation of InGan quantum wells
We have studied the pressure dependence of photoluminescence for various InGaN quantum wells of different Indium compositions. In contrast to classical quantum well systems such as GaAs/AlGaAs, the pressure co...
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Article
The Magnitude of the Piezoelectric Effect in InGaN Quantum Wells
A photoluminescence from a multiquantum GaN/InxGa1−xN/GaN well structure (x varies between 0.1 to 0.4) was investigated at various temperatures, pum** powers. While the temperature dependence of the peak positi...
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Article
Comparative Analysis of Strain and Stress in MBE and MOCVD grown GaN thin films on sapphire
In this study, the causes of biaxial and hydrostatic stress components in epitaxially grown thin GaN films on sapphire are analyzed. It is observed that growth by Molecular Beam Epitaxy (MBE) and by Metal Orga...
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Article
Photoluminescence Characterization of p-type GaN:Mg
We report on results of low-temperature photoluminescence measurements performed on GaN films, grown by molecular beam epitaxy (MBE) on sapphire substrates. The GaN films are either Mg doped (p-type) or consis...
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Article
Photoluminescence of Strain-Engineered MBE-Grown GaN and InGaN Quantum Well Structures
The paper describes the influence of strain on the optical quality of GaN films grown by MBE on c-plane sapphire. The photoluminescence (PL) line width of the donor-bound exciton can be designed to be as narro...
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Article
Three-Dimensional Finite Element Simulation of Electro and Stress Migration Effects in Interconnect Lines
A tool for 3-D modeling of EM and SM in interconnect lines has been developed based on a commercial finite element code. After detailing the approach, we focus on the verification of the simulator by comparing...
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Article
Improved Heteroepitaxial MBE GaN Growth with a Ga Metal Buffer Layer
We demonstrate that the use of pure gallium (Ga) as a buffer layer results in improved crystal quality of GaN epilayers grown by plasma-assisted molecular beam epitaxy on c-plane sapphire. The resulting epilayers...
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Article
Surface States at LT GaAs-n+ GaAs Interfaces
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Article
Surface Acoustic Wave Detection of Large Lattice Relaxation of Metastable EL2 in LT-GaAs
For the first time, surface acoustic waves (SAWs) were used to study the lattice relaxation of metastable defects. A persistent increase of as much as 0.4% of the SAW velocity at low temperatures was observed ...
