Overgrowth of GaN on GaN nanowires produced by mask-less etching

Frajtag, Pavel; Hosalli, A. M.; Samberg, Joshua P.; Colter, P. C.; Paskova, T.; El‐Masry, N. A.; Bedair, S. M.

doi:10.1016/j.jcrysgro.2011.12.055

Cited by 4 publications

(1 citation statement)

References 20 publications

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“…Wurtzite GaN NWs are usually grown 36 or etched vertically, 47 along the bulk crystalline c-axis, and can have triangular, hexagonal, or quasi-circular cross-sections, depending on the details of processing. [35][36][37][38][39] In silicon, simulation of electronic transport in rough cylindrical, square, and atomistically realistic nanowires yields results that are remarkably close to one another, both qualitatively and quantitatively, when these differently shaped wires have similar crosssectional feature size and similar edge roughness features; for instance, the electron mobility in a rough cylindrical wire of diameter equal to 8 nm 48 is very close to the mobility in a square NW with an 8-nm side.…”

Section: Electronic Transportmentioning

confidence: 99%

Ultrathin GaN nanowires: Electronic, thermal, and thermoelectric properties

et al. 2014

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We present a comprehensive computational study of the electronic, thermal, and thermoelectric (TE) properties of gallium nitride nanowires (NWs) over a wide range of thicknesses (3-9 nm), doping densities (10 18 -10 20 cm −3 ), and temperatures (300-1000 K). We calculate the low-field electron mobility based on ensemble Monte Carlo transport simulation coupled with a self-consistent solution of the Poisson and Schrödinger equations. We use the relaxation-time approximation and a Poisson-Schrodinger solver to calculate the electron Seebeck coefficient and thermal conductivity. Lattice thermal conductivity is calculated using a phonon ensemble Monte Carlo simulation, with a real-space rough surface described by a Gaussian autocorrelation function. Throughout the temperature range, the Seebeck coefficient increases while the lattice thermal conductivity decreases with decreasing wire cross section, both boding well for TE applications of thin GaN NWs. However, at room temperature these benefits are eventually overcome by the detrimental effect of surface roughness scattering on the electron mobility in very thin NWs. The highest room-temperature ZT of 0.2 is achieved for 4-nm-thick NWs, while further downscaling degrades it. In contrast, at 1000 K, the electron mobility varies weakly with the NW thickness owing to the dominance of polar optical phonon scattering and multiple subbands contributing to transport, so ZT increases with increasing confinement, reaching 0.8 for optimally doped 3-nm-thick NWs. The ZT of GaN NWs increases with increasing temperature beyond 1000 K, which further emphasizes their suitability for high-temperature TE applications.

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Section: Electronic Transportmentioning

confidence: 99%

Ultrathin GaN nanowires: Electronic, thermal, and thermoelectric properties

et al. 2014

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GaN nanostructures by reactive ion etching: Mask and Maskless approach

Lohani

Varshney

Rawal

et al. 2019

Nano-Structures & Nano-Objects

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Gallium nitride nanowires by maskless hot phosphoric wet etching

Bharrat

Hosalli

Broeck

et al. 2013

Applied Physics Letters

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We demonstrate gallium nitride (GaN) nanowires formation by controlling the selective and anisotropic etching of N-polar GaN in hot phosphoric acid. Nanowires of ∼109/cm,2 total height of ∼400 nm, and diameters of 170–200 nm were obtained. These nanowires have both non-polar {11¯00}/ {112¯0} and semi-polar {1011¯} facets. X–Ray Diffraction characterization shows that screw dislocations are primarily responsible for preferential etching to create nanowires. Indium gallium nitride multi-quantum wells (MQWs) grown on these GaN nanowires showed a blue shift in peak emission wavelength of photoluminescence spectra, and full width at half maximum decreased relative to MQWs grown on planar N-polar GaN, respectively.

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Overgrowth of GaN on GaN nanowires produced by mask-less etching

Cited by 4 publications

References 20 publications

Ultrathin GaN nanowires: Electronic, thermal, and thermoelectric properties

Ultrathin GaN nanowires: Electronic, thermal, and thermoelectric properties

GaN nanostructures by reactive ion etching: Mask and Maskless approach

Gallium nitride nanowires by maskless hot phosphoric wet etching

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