Abstract
Semiconductor light sources operating in the ultraviolet (UV)-C band (100-280 nm) are in demand for a broad range of applications but suffer from extremely low efficiency. AlGaN nanowire photonic crystals promise to break the efficiency bottleneck of deep UV photonics. We report, for the first time, site-controlled epitaxy of AlGaN nanowire arrays with Al incorporation controllably varied across nearly the entire compositional range. It is also observed that an Al-rich AlGaN shell structure is spontaneously formed, significantly suppressing nonradiative surface recombination. An internal quantum efficiency up to 45% was measured at room-temperature. We have further demonstrated large area AlGaN nanowire LEDs operating in the UV-C band on sapphire substrate, which exhibit excellent optical and electrical performance, including a small turn-on voltage of ~4.4 V and an output power of ~0.93 W/cm2 at a current density of 252 A/cm2. The controlled synthesis of AlGaN subwavelength nanostructures with well-defined size, spacing, and spatial arrangement and tunable emission opens up new opportunities for developing high efficiency LEDs and lasers and promises to break the efficiency bottleneck of deep UV photonics.
Original language | English |
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Pages (from-to) | 30494-30502 |
Number of pages | 9 |
Journal | Optics Express |
Volume | 25 |
Issue number | 24 |
DOIs | |
State | Published - Nov 27 2017 |
Externally published | Yes |
Funding
US Army Research Office (W911NF-17-1-0109). Aberration-corrected STEM was performed in the Canadian Centre for Electron Microscopy, a national facility supported by NSERC, the Canada Foundation for Innovation, and McMaster University. S.Y.W. and G.A.B. thank T. Casagrande for the sample preparation using FIB. Aberration-corrected STEM was performed in the Canadian Centre for Electron Microscopy, a national facility supported by NSERC, the Canada Foundation for Innovation, and McMaster University. S.Y.W. and G.A.B. thank T. Casagrande for the sample preparation using FIB.
Funders | Funder number |
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Army Research Office | W911NF-17-1-0109 |
McMaster University | |
Natural Sciences and Engineering Research Council of Canada | |
Canada Foundation for Innovation |