Growth of GaN nanowall network on Si (111) substrate by molecular beam epitaxy

Zhong, Aihua; Hane, Kazuhiro

doi:10.1186/1556-276x-7-686

Cited by 40 publications

(30 citation statements)

References 27 publications

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“…[18][19][20][21][22] The N to Ga ratio also determines the width of the nanowalls as reported previously.…”

Section: Structural Properties Of Lmbe Grown Homoepitaxial Gan Nanostsupporting

confidence: 53%

“…Recently, a few research groups have reported the growth of GaN nanowall networks on sapphire 18,21 and Si(111) 19,20 using plasma assisted molecular beam epitaxy (PA-MBE). Most of the GaN nanowall networks have been grown heteroepitaxially on these substrates under extremely high N to Ga ux ratio conditions.…”

Section: 18-22mentioning

confidence: 99%

“…The LMBE growth of GaN layers was monitored by in situ RHEED and the typical RHEED pattern obtained for the GaN template and the LMBE grown GaN sample along [11][12][13][14][15][16][17][18][19][20] and directions have been presented in Fig. 1(a and b).…”

Section: Structural Properties Of Lmbe Grown Homoepitaxial Gan Nanostmentioning

confidence: 99%

“…19 In case of porous GaN nanowall networks grown on SiC using ion beam assisted MBE at different substrate temperatures (750 and 850 C), the N ion to Ga atom ratio is reported to be between 2.7 and 6.3. 15 Thus, in MBE GaN growth, the N to Ga ux ratio determines the growth mode and the structure of GaN lms.…”

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confidence: 99%

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Structural, optical and electronic properties of homoepitaxial GaN nanowalls grown on GaN template by laser molecular beam epitaxy

et al. 2015

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aWe have grown homoepitaxial GaN nanowall networks on GaN template using an ultra-high vacuum laser assisted molecular beam epitaxy system by ablating solid GaN target under a constant r.f. nitrogen plasma ambient. The effect of laser repetition rate in the range of 10 to 30 Hz on the structural properties of the GaN nanostructures has been studied using high resolution X-ray diffraction, field emission scanning electron microscopy and Raman spectroscopy. The variation of the laser repetition rate affected the tip width and pore size of the nanowall networks. The z-profile Raman spectroscopy measurements revealed the GaN nanowall network retained the same strain present in the GaN template. The optical properties of these GaN nanowall networks have been studied using photoluminescence and ultrafast spectroscopy and an enhancement of optical band gap has been observed for the nanowalls having a tip width of 10-15 nm due to the quantum carrier confinement effect at the wall edges. The electronic structure of the GaN nanowall networks has been studied using X-ray photoemission spectroscopy and it has been compared to the GaN template. The calculated Ga/N ratio is largest ($2) for the GaN nanowall network grown at 30 Hz. Surface band bending decreases for the nanowall network with the lowest tip width. The homoepitaxial growth of porous GaN nanowall networks holds promise for the design of nitride based sensor devices.

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“…[18][19][20][21][22] The N to Ga ratio also determines the width of the nanowalls as reported previously.…”

Section: Structural Properties Of Lmbe Grown Homoepitaxial Gan Nanostsupporting

confidence: 53%

Section: 18-22mentioning

confidence: 99%

Section: Structural Properties Of Lmbe Grown Homoepitaxial Gan Nanostmentioning

confidence: 99%

mentioning

confidence: 99%

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Structural, optical and electronic properties of homoepitaxial GaN nanowalls grown on GaN template by laser molecular beam epitaxy

et al. 2015

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“…Most of the growth of porous GaN is achieved by top down approaches such as chemical etching 19 or ion bombardment 20 , which limit the device performance due to contamination, undesired interface and defect states, and degradation in crystallinity and composition. Previously, we have shown that by controlling V/III ratio, spontaneous formation of porous nanostructures can be achieved by using PA-MBE system, 21-24 which was followed by a few groups [25][26][27][28] . Investigations of the growth process of NwN are highly important to control shape and size of the pores, to enhance light extraction efficiency 22 .…”

Section: Introductionmentioning

confidence: 99%

Edge enhanced growth induced shape transition in the formation of GaN nanowall network

Nayak

Kumar

Shivaprasad

2018

Journal of Applied Physics

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We address the mechanism of early stages of growth and shape transition of the unique nanowall network (NwN) nanostructure of GaN by experimentally monitoring its controlled growth using PA-MBE and complementing it by first-principles calculations.Using electron microscopy, we observe the formation of tetrahedron shaped (3 faced pyramid) islands at early stages of growth, which later grows anisotropically along their edges of the (2021) facets, to form the wall like structure. The mechanism of this crystal growth is discussed in light of surface free energies of the different surfaces, adsorption energy and diffusion barrier of Ga ad-atoms on the (2021) facets. By firstprinciples calculations, we find that the diffusion barrier of ad-atoms decreases with decreasing width of facets, and is responsible for the anisotropic growth and formation of the nanowall network. This study suggest that formation of NwN is a archetype example of structure dependent attachment kinetic (SDAK) instability induced shape transition in thin film growth.

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Nanostructuring GaN thin film for enhanced light emission and extraction

Nayak

Shamoon

Ghatak

et al. 2016

Physica Status Solidi (a)

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We demonstrate here that nanostructuring of GaN thin film significantly enhances the band‐edge emission, due to structural and geometrical effects. Films of increasing roughness are formed by kinetic control in a PA‐MBE system and their morphological, structural and optical properties are compared by complementary characterization probes. The nanowall configuration with largest pore size (≈215 nm) shows a two orders of magnitude enhancement of integrated PL intensity in comparison to a GaN epilayer. Finite difference time domain (FDTD) simulation is performed to explain the role of total internal reflection and scattering on light extraction. The extended defects terminate proximal to interface, leading to most regions of the nanowalls are defect free, enhancing light generation. The observation of broad HRXRD rocking curves is attributed to a mosaicity that originates due to mutual misorientation of the nanowalls. Thus, the low dislocation density in the nanowalls and their suitable geometry promotes high light emission and extraction, respectively, offering this nanostructure as a potential material for high brightness LED fabrication.

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Growth of GaN nanowall network on Si (111) substrate by molecular beam epitaxy

Cited by 40 publications

References 27 publications

Structural, optical and electronic properties of homoepitaxial GaN nanowalls grown on GaN template by laser molecular beam epitaxy

Structural, optical and electronic properties of homoepitaxial GaN nanowalls grown on GaN template by laser molecular beam epitaxy

Edge enhanced growth induced shape transition in the formation of GaN nanowall network

Nanostructuring GaN thin film for enhanced light emission and extraction

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