Gallium nitride nanowires by maskless hot phosphoric wet etching

Bharrat, D.; Hosalli, A. M.; Broeck, D. M. Van Den; Samberg, Joshua P.; Bedair, S. M.; El‐Masry, N. A.

doi:10.1063/1.4819272

Cited by 9 publications

(6 citation statements)

References 12 publications

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“…From SEM analysis of the as-etched pyramidal nanowires, the estimated angle of the top semipolar facet was 12°from the [0001] c-direction, which was consistent across different nanowires and at different etch times. Previously, it has been reported that H 3 PO 4 etches N-face ( ¯) 0001 GaN into dodecagonal pyramids [59][60][61][62] and etches hexagonal pits at defect sites in Ga-face ( ) 0001 GaN [61,[63][64][65][66]. Thus, the H 3 PO 4 etch for GaN can be considered crystallographic in nature, much like the KOH-based etch, but with semipolar rather than nonpolar planes being exposed.…”

Section: Gan Nanowires Etched In H 3 Pomentioning

confidence: 99%

Fabrication and field emission properties of vertical, tapered GaN nanowires etched via phosphoric acid

Kazanowska¹,

Sapkota²,

Lu³

et al. 2021

Nanotechnology

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The controlled fabrication of vertical, tapered, and high-aspect ratio GaN nanowires via a two-step top-down process consisting of an inductively coupled plasma reactive ion etch followed by a hot, 85% H3PO4 crystallographic wet etch is explored. The vertical nanowires are oriented in the direction and are bound by sidewalls comprising of semipolar planes which are at a 12° angle from the [0001] axis. High temperature H3PO4 etching between 60 °C and 95 °C result in smooth semipolar faceting with no visible micro-faceting, whereas a 50 °C etch reveals a micro-faceted etch evolution. High-angle annular dark-field scanning transmission electron microscopy imaging confirms nanowire tip dimensions down to 8–12 nanometers. The activation energy associated with the etch process is 0.90 ± 0.09 eV, which is consistent with a reaction-rate limited dissolution process. The exposure of the type planes is consistent with etching barrier index calculations. The field emission properties of the nanowires were investigated via a nanoprobe in a scanning electron microscope as well as by a vacuum field emission electron microscope. The measurements show a gap size dependent turn-on voltage, with a maximum current of 33 nA and turn-on field of 1.92 V nm−1 for a 50 nm gap, and uniform emission across the array.

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Section: Gan Nanowires Etched In H 3 Pomentioning

confidence: 99%

Fabrication and field emission properties of vertical, tapered GaN nanowires etched via phosphoric acid

Kazanowska¹,

Sapkota²,

Lu³

et al. 2021

Nanotechnology

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“…Several chemical solutions have been previously demonstrated for wet etching of GaN, including KOH, H 3 PO 4 , and tetramethylammonium hydroxide (TMAH), [7][8][9] although in general these etches require elevated temperatures and high concentrations in order to produce useful etch rates, and the resulting surface morphology and etch performance is often poor for device applications. Photoelectrochemical (PEC) etching offers significant advantages; the use of optical illumination to generate electron-hole pairs near the surface during the etch process allows for additional flexibility such as dopant-and bandgap-selective etching.…”

Section: Introductionmentioning

confidence: 99%

Faceted sidewall etching of n-GaN on sapphire by photoelectrochemical wet processing

Yue¹,

Yan²,

Li³

et al. 2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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A wet etch process that produces smooth sidewalls aligned with the m-plane ({1 100}) crystal facets of Ga-polar GaN grown on sapphire is demonstrated by combining photo-electrochemical (PEC) treatment with a postprocessing wet etch step. This novel process results in faceted and extremely smooth vertical etched sidewalls. This two-step process consists of a PEC treatment to define the geometry by converting the region to be removed to an oxide, followed by selective wet-chemical removal of the oxide in buffered HF and post-etch immersion in KOH (0.5 M) at 150 C to smooth the surface and reveal the crystal planes. The dependence of the PEC treatment parameters (optical intensity, solution composition, direct current bias) on the resulting etch rates and morphology has been investigated.

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“…A flexible GaN membrane platform on a silicon wafer developed by eutectic bonding and a laser lift-off process offers flexibility for the stable and reliable design of various pixel shapes and related manufacturing processes. Flexible GaN has also been developed using other techniques such as the selective anisotropic etching of N-polar GaN in hot phosphoric acid [ 97 ]. However, there are few reports on the preparation of flexible GaN via electrochemical etching methods.…”

Section: Synthesis Methods For (In)gan Nanostructuresmentioning

confidence: 99%

In(Ga)N Nanostructures and Devices Grown by Molecular Beam Epitaxy and Metal-Assisted Photochemical Etching

Soopy

Tang

et al. 2021

Nanomaterials

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This review summarizes the recent research on nitride nanostructures and their applications. We cover recent advances in the synthesis and growth of porous structures and low-dimensional nitride nanostructures via metal-assisted photochemical etching and molecular beam epitaxy. The growth of nitride materials on various substrates, which improves their crystal quality, doping efficiency, and flexibility of tuning performance, is discussed in detail. Furthermore, the recent development of In(Ga)N nanostructure applications (light-emitting diodes, lasers, and gas sensors) is presented. Finally, the challenges and directions in this field are addressed.

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Gallium nitride nanowires by maskless hot phosphoric wet etching

Cited by 9 publications

References 12 publications

Fabrication and field emission properties of vertical, tapered GaN nanowires etched via phosphoric acid

Fabrication and field emission properties of vertical, tapered GaN nanowires etched via phosphoric acid

Faceted sidewall etching of n-GaN on sapphire by photoelectrochemical wet processing

In(Ga)N Nanostructures and Devices Grown by Molecular Beam Epitaxy and Metal-Assisted Photochemical Etching

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