352-nm Laser Diodes Enabled by Low-Dislocation-Density AlGaN Templates
Abstract not provided.
Publications
Pathways to Ultra-Efficient Solid-State Lighting (invited)
Abstract not provided.
Low-Dislocation-Density AlGaN Templates for UV Laser Diodes (invited)
Abstract not provided.
Understanding and Controlling Deep Level Defects for Next-Generation Power Electronics (invited)
Abstract not provided.
Detection and Modeling of Electrical Leakage Current in AlGaN-Based Deep Ultraviolet Light-Emitting Diodes
Abstract not provided.
LEEM-PEEM study of surface defects surface potential and compositional inhomogeneities in InGaN-based heterostructures
Abstract not provided.
Electrical current leakage and open-core threading dislocations in AlGaN-based deep ultraviolet light-emitting diodes
Journal of Applied Physics
Electrical current transport through leakage paths in AlGaN-based deep ultraviolet (DUV) light-emitting diodes (LEDs) and their effect on LED performance are investigated. Open-core threading dislocations, or nanopipes, are found to conduct current through nominally insulating Al 0.7Ga0.3N layers and limit the performance of DUV-LEDs. A defect-sensitive phosphoric acid etch reveals these open-core threading dislocations in the form of large, micron-scale hexagonal etch pits visible with optical microscopy, while closed-core screw-, edge-, and mixed-type threading dislocations are represented by smaller and more numerous nanometer-scale pits visible by atomic-force microscopy. The electrical and optical performances of DUV-LEDs fabricated on similar Si-doped Al0.7Ga0.3N templates are found to have a strong correlation to the density of these nanopipes, despite their small fraction (<0.1% in this study) of the total density of threading dislocations. © 2014 AIP Publishing LLC.
Effect of Thickness and Carrier Density on the Optical Polarization and Extraction Efficiency of 275 nm UVLEDs
Abstract not provided.
Strong Sensitivity of Si Doping Efficiency and Deep Level Formation on Growth Temperature for n-type Al0.7Ga0.3N
Abstract not provided.
Anisotropic Optical Polarization of AlGaN Based 275 nm Light-Emitting Diodes due to Quantum-Size Effects
Abstract not provided.
The Energy Frontier Research Center for Solid-State Lighting Science: Exploring New Materials Architectures and Light Emission Phenomena
Journal of Physical Chemistry C
Abstract not provided.
Connection between GaN and InGaN Growth Mechanisms and Surface Morphology
Journal of Crystal Growth
Abstract not provided.
Contribution of Deep Level Defects to Decreasing Radiative Efficiency of InGaN/GaN Quantum Wells with Increasing Emission Wavelength
Applied Physics Letters
Abstract not provided.
Low Dislocation Density AlGaN Epilayers by Epitaxial Overgrowth of Patterned Templates
Journal of Crystal Growth
Abstract not provided.
Distribution of Deep Level Defects in InGaN/GaN LEDs and their Dependence on In Alloying
Abstract not provided.
Material and Device Development of AlGaN Based Deep UV Emitters
Abstract not provided.
Quantifying Surface Mounding of GaN and InGaN Thin Films
Abstract not provided.
Deep Level Defect Spectroscopy in Reduced Dimension Semiconductor Materials and Devices
Abstract not provided.
Using Dilute Hydrogen Flows to Tailor Indium Incorporation during InGaN Growth
Abstract not provided.
Semi-polar GaN materials technology for high IQE green LEDs
The goal of this NETL funded program was to improve the IQE in green (and longer wavelength) nitride- based LEDs structures by using semi-polar GaN planar orientations for InGaN multiple quantum well (MQW) growth. These semi-polar orientations have the advantage of significantly reducing the piezoelectric fields that distort the QW band structure and decrease electron-hole overlap. In addition, semipolar surfaces potentially provide a more open surface bonding environment for indium incorporation, thus enabling higher indium concentrations in the InGaN MQW. The goal of the proposed work was to select the optimal semi-polar orientation and explore wafer miscuts around this orientation that produced the highest quantum efficiency LEDs. At the end of this program we had hoped to have MQWs active regions at 540 nm with an IQE of 50% and an EQE of 40%, which would be approximately twice the estimated current state-of-the-art.
Deep Level Defect Spectroscopy in Reduced Dimension Semiconductor Materials and Devices (invited)
Abstract not provided.
Highly Nonlinear Defect-Induced Carrier Recombination Rates in Semiconductors
Physical Review B
Abstract not provided.
Magnetic Field Induced Quench of Photoluminescence in La0.7Sr0.3MnO3 Nanopillars Embedded in Self-Assembled Vertically Aligned Epitaxial (ZnO)0.5:(La0.7Sr0.3MnO3)0.5 Nanocomposite Films
Proposed for publication in Applied Physics Letters.
Abstract not provided.
Nanofabrication of tunable nanowire lasers via electron and ion-beam based techniques
Abstract not provided.
Quantitative and Depth-Resolved Deep Level Defect Distributions in InGaN/GaN Light Emitting Diodes
Proposed for publication in Optics Materials Express.
Abstract not provided.
Results 126–150 of 251