Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes

Journal Article · Mon Jan 28 04:00:00 EST 2013 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4789512· OSTI ID:22162692

Verma, Jai; Kandaswamy, Prem Kumar; Protasenko, Vladimir; Verma, Amit; Grace Xing, Huili; Jena, Debdeep ^[1]

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1. Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.

• OSTI ID: 22162692
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 4 Vol. 102; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ALIGNMENT
ALUMINIUM NITRIDES
CONFINEMENT
CRYSTAL DEFECTS
EFFICIENCY
ELECTROLUMINESCENCE
GALLIUM NITRIDES
LAYERS
LIGHT EMITTING DIODES
MOLECULAR BEAM EPITAXY
OSCILLATOR STRENGTHS
POLARIZATION
QUANTUM DOTS
SEMICONDUCTOR MATERIALS
STARK EFFECT
TEMPERATURE RANGE 0273-0400 K
TUNNEL EFFECT
ULTRAVIOLET RADIATION
WAVELENGTHS