Publications

Moseley, Michael; Allerman, A.A.; Crawford, Mary H.; Wierer, Jonathan W.; Smith, Michael; Armstrong, Andrew A.

Abstract not provided.

ACS Photonics

Benz, Alexander; Campione, Salvatore; Moseley, Michael; Wierer, Jonathan W.; Allerman, A.A.; Wendt, J.R.; Brener, Igal B.

(Figure Presented) We present the design, realization, and characterization of optical strong light-matter coupling between intersubband transitions within a semiconductor heterostructures and planar metamaterials in the near-infrared spectral range. The strong light-matter coupling entity consists of a III-nitride intersubband superlattice heterostructure, providing a two-level system with a transition energy of ∼0.8 eV (λ ∼1.55 μm) and a planar "dogbone" metamaterial structure. As the bare metamaterial resonance frequency is varied across the intersubband resonance, a clear anticrossing behavior is observed in the frequency domain. This strongly coupled entity could enable the realization of electrically tunable optical filters, a new class of efficient nonlinear optical materials, or intersubband-based light-emitting diodes.

Journal of Applied Physics

Moseley, Michael; Allerman, A.A.; Crawford, Mary H.; Wierer, Jonathan W.; Smith, Michael; Biedermann, Laura B.

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.

Wierer, Jonathan W.; Montano, Ines M.; Crawford, Mary H.; Moseley, Michael; Allerman, A.A.

Abstract not provided.

Armstrong, Andrew A.; Moseley, Michael; Allerman, A.A.; Crawford, Mary H.; Wierer, Jonathan W.

Abstract not provided.

Wierer, Jonathan W.; Montano, Ines M.; Crawford, Mary H.; Allerman, A.A.; Moseley, Michael

Abstract not provided.