Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes

Compact solid-state lamps based on light-emitting diodes (LEDs) are of current technological interest as an alternative to conventional light bulbs. The brightest LEDs available so far emit red light and exhibit higher luminous efficiency than fluorescent lamps. If this luminous efficiency could be...

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Bibliographic Details
Published in:Nature (London) 2000-08, Vol.406 (6798), p.865-868
Main Authors: Waltereit, P, Brandt, O, Trampert, A, Grahn, H. T, Menniger, J, Ramsteiner, M, Reiche, M, Ploog, K. H
Format: Article
Language:English
Subjects:
Applied sciences
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Diodes
Ecological effects
Ecology
Economics
Electronics
Electrostatic fields
Exact sciences and technology
Fabrication
Fluorescent lamps
Gallium nitrides
Humanities and Social Sciences
Iii-v semiconductors
letter
Light
Light-emitting diodes
multidisciplinary
Nitrides
Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation
Optical properties of specific thin films
Optoelectronic devices
Physics
Power consumption
Science
Science (multidisciplinary)
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Semiconductors
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Summary:Compact solid-state lamps based on light-emitting diodes (LEDs) are of current technological interest as an alternative to conventional light bulbs. The brightest LEDs available so far emit red light and exhibit higher luminous efficiency than fluorescent lamps. If this luminous efficiency could be transferred to white LEDs, power consumption would be dramatically reduced, with great economic and ecological consequences. But the luminous efficiency of existing white LEDs is still very low, owing to the presence of electrostatic fields within the active layers. These fields are generated by the spontaneous and piezoelectric polarization along the [0001] axis of hexagonal group-III nitrides-the commonly used materials for light generation. Unfortunately, as this crystallographic orientation corresponds to the natural growth direction of these materials deposited on currently available substrates. Here we demonstrate that the epitaxial growth of GaN/(Al,Ga)N on tetragonal LiAlO2 in a non-polar direction allows the fabrication of structures free of electrostatic fields, resulting in an improved quantum efficiency. We expect that this approach will pave the way towards highly efficient white LEDs.
ISSN:0028-0836
1476-4687
DOI:10.1038/35022529