Radial GaN Nanowire‐Based LEDs

Li, Shunfeng

doi:10.1002/9781118984291.ch6

Cited by 1 publication

(1 citation statement)

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“…To date, most published accounts of NW-based UV LEDs report on axial structures, grown either by random nucleation processes [2,5,6,[8][9][10][11][12]14] or Ga-polar selective area epitaxy [7], or on randomly nucleated core-shell structures [15]. While core-shell LEDs based on selective area growth are widely reported for visible-wavelength emitters [16], relatively few reports exist on fully conformal core-shell UV LEDs [3]. However, NWs grown by N-polar selective area epitaxy [17] present several favorable attributes including high-aspect ratios for large LED active regions, arbitrarily large pitch spacings suitable for growth of single NWs with core-shell geometry, and integration with silicon substrates for potential integration with CMOS driver circuitry.…”

Section: Introductionmentioning

confidence: 99%

UV LEDs based on p–i–n core–shell AlGaN/GaN nanowire heterostructures grown by N-polar selective area epitaxy

et al. 2019

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Ultraviolet light-emitting diodes fabricated from N-polar AlGaN/GaN core-shell nanowires (NWs) with p-in structure produced electroluminescence at 365 nm with ∼5× higher intensities than similar GaN homojunction LEDs. The improved characteristics were attributed to localization of spontaneous recombination to the NW core, reduction of carrier overflow losses through the NW shell, and elimination of current shunting. Poisson-drift-diffusion modeling indicated that a shell Al mole fraction of x=0.1 in Al x Ga 1−x N effectively confines electrons and injected holes to the GaN core region. AlGaN overcoat layers targeting this approximate Al mole fraction were found to possess a low-Al-content tip and high-Al-content shell, as determined by scanning transmission electron microscopy. Photoluminescence spectroscopy further revealed the actual Al mole fraction to be NW diameter-dependent, where the tip and shell compositions converged towards the nominal flux ratio for large diameter NWs.

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