Open AccessSelective area epitaxy of AlGaN nanowire arrays across nearly the entire compositional range for deep ultraviolet photonics
Author(s) -
Xianhe Liu,
Binh Huy Le,
Steffi Y. Woo,
Songrui Zhao,
Alexandre Pofelski,
Gianluigi A. Botton,
Zetian Mi
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.030494
Subject(s) - materials science , optoelectronics , nanowire , photonics , light emitting diode , ultraviolet , quantum efficiency , substrate (aquarium) , sapphire , epitaxy , laser , optics , nanotechnology , oceanography , physics , layer (electronics) , geology
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/cm 2 at a current density of 252 A/cm 2 . 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.