Lighting for the 21st century with laser diodes based on non-basal plane orientations of GaN
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Lighting for the 21st century with laser diodes based on non-basal plane orientations of GaN Leah Y. Kuritzky and James S. Speck*, Materials Department, University of California, Santa Barbara, CA 93106, USA Address all correspondence to Leah Y. Kuritzky at [email protected] (Received 27 April 2015; accepted 7 July 2015)
Abstract More than two decades of III-N materials research has led to the production of visible spectrum commercial light-emitting diodes (LEDs) and laser diodes (LDs). Commercial c-plane LEDs are currently limited by efficiency droop which describes the decline in efficiency with increasing input current density. Laser-based sources, however, provide peak efficiencies at much higher current densities and may circumvent efficiency droop limitations. The potential benefits of non-basal plane (NBP) orientations could accelerate the evolution of solid-state lighting from LED to LD sources. Here, we review the progress in long-wavelength (440–590 nm) NBP quantum well LD research and discuss applications in solidstate lighting, visible light communication and smart lighting.
The (Al,Ga,In)N materials system has impacted energy efficiency on the worldwide scale through its application to blue lightemitting diodes (LEDs). This impact on technology and society was recognized by the award of the 2014 Nobel Prize in Physics to Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura. These researchers persevered in their pursuit of this difficult materials system despite the popularity of the competing ZnSe-based system and the widespread scientific opinion that the high dislocation density (>109 cm−2) of III-N films would prevent their application to any useful device.[1] The breakthroughs in III-N crystal growth led to the demonstration of high-brightness GaN-based blue and green LEDs by Shuji Nakamura in 1993– 1995.[2,3] After those demonstrations, interest in III-N materials grew rapidly, and the ZnSe system was rendered obsolete for light-emitting applications. Since then, cost reductions and performance improvements have brought GaN-based LEDs into the mainstream, supplanting outdated lighting technology and dramatically improving energy efficiency. As a result of the increased interest in III-N materials since the early 1990s, not only have blue LEDs improved to the point of widespread commercialization, but also many new properties of the III-N materials system have been identified, explained, and applied to new innovations. The direct, wide band gap of III-N semiconductors makes them promising for solar cell materials[4,5] intended for ultra-high-efficiency multi-junction stacks.
* This author was a member of the Advisory Board of this journal during the review and decision stage. Advisory Board members do not sit on the editorial board, and so fall under the “Non-Editors“ section of the Materials Research Society policy on review and publication of manuscripts to be found at http://www. mrs.org/editor-manuscripts/.
High-frequency GaN electronic devices for power switching applications offe
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