Growth of large-scale GaN nanowires and tubes by direct reaction of Ga with NH3

He, Maoqi; Minus, Indira; Zhou, P.; Mohammed, Shakil; Halpern, Joshua B.; Jacobs, R. N.; Sarney, Wendy L.; Salamanca‐Riba, L.; Vispute, R. D.

doi:10.1063/1.1329863

Cited by 203 publications

(112 citation statements)

References 14 publications

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“…It has been reported that hydrogen has a higher surface mobility and can stream easier and faster than the products of GaN molecules. 26 Therefore, hydrogen has a higher tendency to occupy the surface defects on the substrate, which behave as heterogeneous GaN nucleation sites. When the GaN molecules encounter the surface defects created by hydrogen, the large number of nucleation sites enhances the probability of the random growth of GaN crystals.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Nanoscale Protrusions on Field-Emission Properties for GaN Nanowires

Lee

Shin

Chen

et al. 2007

J. Electrochem. Soc.

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GaN nanowires ͑NWs͒ have been synthesized on platinum-coated silicon͑111͒ substrates by the chemical vapor deposition ͑CVD͒ method under different NH 3 /H 2 carrier gas-flow rate ratios. X-ray diffractometer and transmission electron microscope analyses indicate that GaN NWs have wurtzite structures. Nanoscale protrusions with crystal orientation along the ͓002͔ direction were observed on the surface of GaN NWs grown under high H 2 flow rate conditions. As compared to the field-emission result of GaN NWs with smooth surfaces, GaN NWs with nanoscale protrusions exhibit a lower turn-on field of 8.5 V/m and a higher field-enhancement factor of ␤ = 315. These nanoscale protrusions are believed to account for the enhancement of the fieldemission behaviors of GaN NWs. Gallium nitride ͑GaN͒ has a wide direct bandgap of 3.4 eV at room temperature and is a popular semiconductor material with potential applications in blue and UV light emission, high temperature, and high power electronic devices.1,2 Recent efforts have been devoted to carbon nanotubes ͑CNTs͒ and ZnO nanostructures to improve the performance of conventional Spindt-type Mo field emitters. Because Mo, CNTs, and ZnO have a work function around 4.5 eV, sharp needlelike nanostructures are required to enhance electron emission with sufficient current density. GaN has attractive properties as a material for field emitters, e.g., a lower work function ͑4.1 eV͒ and stronger chemical and mechanical stability than those listed above. These properties make it a desired alternative material for field emitters. Typical GaN nanostructure morphologies include nanowires ͑NWs͒, nanorods, nanobelts, and nanotubes. Recently, needlelike 3 structures and quasi-aligned 4 GaN NWs have been grown and studies have shown that the sharp tip is responsible for the enhancement of the field-emission ͑FE͒ properties of NWs. The resulting turn-on field is ϳ7.5 V/m for needlelike 3 GaN NWs and ϳ7.0 V/m for quasi-aligned 4 GaN NWs. In these studies, the electrons were emitted from the tip of the NW due to its high aspect ratio. The FE characteristics of various GaN NWs created from different synthesizing methods are listed in Table I. All the GaN NWs listed in this table were grown under a constant flow rate of NH 3 . However, no study has ever been performed with different carrier gases, such as H 2 . This report not only shows the effect of different NH 3 /H 2 flow rate ratios on the growth and FE properties but also demonstrates the ability to use platinum as the catalyst for GaN NW growth of many other transition metals, such as Fe, Co, Ni, and Au. Nanoscale protrusions with crystal orientation along the ͓002͔ axis were first observed on the surface of GaN NWs that were grown under high H 2 flow rate conditions. The correlation between the FE behaviors and nanoscale protrusions were also explored in this report. ExperimentalGaN NWs were grown by thermally reacting metallic Ga ͑3 g͒ with different ratios of NH 3 /H 2 gases at 950°C for 30 min. In a horizontal quartz-tube furnace with a ...

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Section: Resultsmentioning

confidence: 99%

The Effect of Nanoscale Protrusions on Field-Emission Properties for GaN Nanowires

Lee

Shin

Chen

et al. 2007

J. Electrochem. Soc.

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“…[6] Ammonia was flowed at 50-100 sccm for 3-4 hours, resulting in a matrix of GaN nanowires and platelets on the nitride boat and quartz furnace liner. Typical nanowire dimensions are 20 µm to 100 µm in length and 100 nm to 400 nm in diameter.…”

Section: Experimental Methodsmentioning

confidence: 99%

Electron Beam-induced Light Emission and Transport in GaN Nanowires

Tringe

MoberlyChan

Stevens

et al. 2006

2006 1st International Conference on Nano-Networks and Workshops

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Abstract-We report observations of electron beam-induced light from GaN nanowires grown by chemical vapor deposition. GaN nanowires were modified in-situ with deposited opaque platinum coatings to estimate the extent to which light is channeled to the ends of nanowires. Some evidence of light channeling was found, but wire microstructure and defects play an important role in light scattering and transport, limiting the extent to which light is confined.

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“…This recently reported growth technique [1] demonstrates processing of GaN one-dimensional structures as thin as 26 nm and up to 500 gm in length. This method is both interesting and attractive in that fabrication is carried out without the assistance of template materials as required by other methods.…”

Section: Introductionmentioning

confidence: 99%

Structural Characterization of GaN Nanowires Fabricated via Direct Reaction of Ga Vapor and Ammonia

Jacobs

Salamanca‐Riba

et al. 2001

MRS Proc.

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We report structural studies of large-scale wurtzite GaN nanowires fabricated by direct reaction of Ga vapor and NI3. This recently reported growth technique [1] demonstrates processing of GaN one-dimensional structures as thin as 26 nm and up to 500 gm in length. This method is both interesting and attractive in that fabrication is carried out without the assistance of template materials as required by other methods. In this study, transmission electron microscopy (TEM) is used to characterize the nanowires, while x-ray diffraction (XRD) and energy dispersive x-ray spectroscopy (EDS) data provide supporting structural/compositional analysis. Our structural investigation reveals the presence of thin hexagonal platelets, which we believe play a critical role in the nucleation, growth, and orientation of the wires. In particular, our findings indicate that most of the wires grow along the [ 2110 ] direction, normal to the platelet edges.

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Growth of large-scale GaN nanowires and tubes by direct reaction of Ga with NH3

Cited by 203 publications

References 14 publications

The Effect of Nanoscale Protrusions on Field-Emission Properties for GaN Nanowires

The Effect of Nanoscale Protrusions on Field-Emission Properties for GaN Nanowires

Electron Beam-induced Light Emission and Transport in GaN Nanowires

Structural Characterization of GaN Nanowires Fabricated via Direct Reaction of Ga Vapor and Ammonia

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