Critical assessment 23: Gallium nitride-based visible light-emitting diodes

Authors
Oliver, RA 

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Type
Article
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Abstract

Solid-state lighting based on light-emitting diodes (LEDs) is a technology with the potential to drastically reduce energy usage, made possible by the development of gallium nitride and its alloys. However, the nitride materials family exhibits high defect densities and, in the equilibrium wurtzite crystal phase, large piezo-electric and polarisation fields arising at polar interfaces. These unusual physical properties, coupled with a high degree of carrier localisation in devices emitting visible light, result in ongoing challenges in device development, such as efficiency ‘droop’ (the reduction in efficiency of nitride LEDs with increasing drive current density), the ‘green gap’ (the relatively low efficiency of green emitters in comparison to blue) and the challenge of driving down the cost of LED epitaxy.

Publication Date
2016
Online Publication Date
2016-03-03
Acceptance Date
Keywords
Light-emitting diodes, Gallium nitride, Indium gallium nitride, Green, Efficiency droop, Silicon substrates
Journal Title
Materials Science and Technology (United Kingdom)
Journal ISSN
0267-0836
1743-2847
Volume Title
32
Publisher
Informa UK Limited
Sponsorship
European Research Council (279361)