Surface and optical properties of indium-rich InGaN layers grown on sapphire by migration-enhanced plasma assisted metal organic chemical vapor deposition

Zhang, Chi; Li, Yao; Qian, Yingda; Liang, Yuanlan; Talwar, Devki N.; Huang, San-Yuan; Li, Qingxuan; Seidlitz, Daniel; Dietz, N.; Ferguson, Ian T.; Lu, Xiang; Wan, Lingyu; He, Kai; Feng, Zhe Chuan

doi:10.1088/2053-1591/aae4b5

Cited by 4 publications

(4 citation statements)

References 39 publications

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“…During the centrifugal precipitation of the sample for XPS, an imbalance in the amounts of Na + ions and their anionic counterparts can potentially be caused by the selective washing of lipophilic anions, with the remainder Na + ions being adsorbed on the surface; this may reveal the higher partitioning affinity of Na + ions to the polar surface than the lipophilic anions in the oil continuous phase (in the unprecipitated nonpolar dispersion, most of the Na + ions on the particle surface were probably neutralized in situ by their anionic counterparts, and only a small fraction of them could exist being dissociated, as inferred from the low amounts of surface charges corresponding to the low magnitudes of electrophoretic mobilities). The characteristic Na 1s peak appeared the most distinctively at an etching time of 0 (Figure 6d), indicating that the partitioning of Na + to the dispersed EGaIn phases was primarily caused by the adsorption on the outermost particle surface, and not by the absorption or solubilization into the bulk liquid metal inner phase under the solid oxide surface (the peak at ≈1075 eV found for the spectra at longer etching times was attributed to the In Auger, [58] which was also observed in the sample obtained from the surfactant-free dispersion). Lastly, the surface adsorption of Na + was confirmed by the energy dispersive spectroscopy (EDS) equipped with TEM (Figure 6e).…”

Section: Charging Mechanisms Of Nano Liquid Metals In Doped Nonpolar Liquidsmentioning

confidence: 96%

Electrostatic Stabilization of Nano Liquid Metals in Doped Nonpolar Liquids

Kim

Jeong

Hyun

et al. 2021

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their range of applications could be substantially extended beyond the traditional ones based on liquid metals as a continuous fluid. To date, liquid-metal particles of micro-or nano-sizes have demonstrated promising performances in diverse research areas such as self-healing electronics, [8,9] thermal interface materials, [10,11] catalytic reaction implementation, [12] drug delivery, [13] and plasmonics. [14] Among the various methods developed for manufacturing liquid-metal particles, [15,16] sonication is most commonly employed, [5][6][7] which breaks the bulk liquid metal into small entities in a desired solvent. The dispersed liquid-metal particles have a thin oxide skin that forms spontaneously on a surface, [1] which prevents liquidmetal droplet coalescence and allows them to maintain their particulate form. The modulation of the surface oxide, typically with the support of surface-bound ligands, [17,18] can be used to precisely control the mechanical, electrical, and optical properties of liquid-metal particles that carry the liquid-state core under the outermost oxide surface. This can provide unique opportunities that are inaccessible by conventional all-solid-state metal and metal oxide particles.Despite the large number of studies on the preparation and applications of micro-and nano-sized liquid-metal particles reported to date, less attention has been focused on the colloidal behavior of such particles suspended in liquid media. To the best of our knowledge, no studies have been conducted on liquid-metal colloids in highly nonpolar organic solvents such as saturated hydrocarbons. Nonpolar colloidal dispersions are crucial in various industrial applications, the best-known example of which is the electronic ink embedded in an electrophoretic display. [19][20][21][22] Owing to the low electrical conductivity of nonpolar solvents, the power consumption of electrophoretic displays is low, which can be beneficial in the development of emerging portable and wearable Internet-of-Things (IoT) devices. Thus, classical electronic ink technology was recently combined with a triboelectric nanogenerator (TENG) to develop self-powered and low-power-consumption electronic paper. [23] Other useful applications of nonpolar dispersions include oilbased printing toners for electrostatic lithographic printers, [24] electrorheological fluids, [25,26] photonic crystals, [27] and drug delivery systems. [28] While conventional nonpolar dispersions used in such applications employ all-solid-state particles, new Liquid metals and alloys are attracting renewed attention owing to their potential for application in various advanced technologies. Eutectic galliumindium (EGaIn) has been focused on in particular because of its integrated advantages of high conductivity, low melting point, and low toxicity. In this study, the colloidal behavior of nano-dispersed EGaIn in nonpolar oils is investigated. Although the nonpolar oil continuous phase is commonly considered to be free of electric charges, electrostatic repulsion appears to...

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Section: Charging Mechanisms Of Nano Liquid Metals In Doped Nonpolar Liquidsmentioning

confidence: 96%

Electrostatic Stabilization of Nano Liquid Metals in Doped Nonpolar Liquids

Kim

Jeong

Hyun

et al. 2021

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“…Figure 5 shows the fitting spectra of the narrow N1s and O1s bands of three AlN films. By using XPSPEAK4.1 software [49], Gauss-Lorentz mixture was used. The function performing leads to a fitting analysis on them.…”

Section: Chemical Composition Of the Deposited Aln Films: Xps Spectramentioning

confidence: 99%

Optical and structural properties of AlN thin films deposited on different faces of sapphire substrates

Yin¹,

Zhou²,

Li³

et al. 2021

Semicond. Sci. Technol.

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We report the comprehensive spectroscopic results of AlN thin films deposited on the A-, R- and C-surfaces of sapphire substrates by radio frequency magnetron sputtering. The optical and structural properties of the epitaxial-grown AlN films were characterized using various techniques of high-resolution x-ray diffraction spectroscopy, x-ray photoelectron spectroscopy, Raman scattering spectroscopy, spectroscopic ellipsometry and associated analytical tools. Our large number of measurement results clearly show that sapphire substrates of different polarities have effects on the surface roughness, dislocation density, grain size, microstrain, and surface oxygen binding capacity of the film grown on its surface. The results obtained from Ellipsometry measurements show that the thickness, band gap and roughness of AlN films grown on C-plane sapphire are the smallest among the three samples. After careful analyses of the variable temperature Raman spectra, as the temperature rises from 80 K to 800 K, the AlN film has always exhibited tensile stress. In the same temperature range, the tensile stress of the AlN film grown on the C-plane sapphire has the greatest effect with temperature. The lifetime of E2 (high) phonons gradually decays with the increase of temperature.

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“…[28] SiO 2 (PE-ALD) [7,24,25] β-Ga 2 O 3 (PE-ALD) [38] Silicon nitride (PE-ALD) [22,23,27,31,37,40] Plasma treatment (PE-ALD) [26] Electron treatment (CVD based) [36,39] GaN (CVD based) [42,44,45,55] InN (CVD based) [41][42][43]45,47,48,53,57,58] InGaN (CVD based) [49,51,54,56] InN nanopillars (CVD based) [46,50,52,55] The oxygen contamination overview provided in this introduction is followed by an experimental examination of some effects related to the surface modification of cathode materials by the generated plasma. In particular, we examine changes that have been observed for aluminum and stainless-steel cathodes.…”

Section: Materials (And Process) Referencementioning

confidence: 99%

“…For instance, some of the sharpest InN film photoluminescence ever reported was independently measured by McGill University [47], while some excellent quality epitaxial material has also been achieved [48]. These results came to the early attention of the research group of Nikolaus Dietz of Georgia State University, who upgraded a low-pressure CVD system to operate with a hollow cathode source [51,53,54,56,58]. From there, a group at Bilkent University learned about the low oxygen contamination from these hollow cathode sources.…”

Section: Materials (And Process) Referencementioning

confidence: 99%

Recent Advances in Hollow Cathode Technology for Plasma-Enhanced ALD—Plasma Surface Modifications for Aluminum and Stainless-Steel Cathodes

Butcher

Georgiev²,

Georgieva³

2021

Coatings

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Recent designs have allowed hollow cathode gas plasma sources to be adopted for use in plasma-enhanced atomic layer deposition with the benefit of lower oxygen contamination for non-oxide films (a brief review of this is provided). From a design perspective, the cathode metal is of particular interest since—for a given set of conditions—the metal work function should determine the density of electron emission that drives the hollow cathode effect. However, we found that relatively rapid surface modification of the metal cathodes in the first hour or more of operation has a stronger influence. Langmuir probe measurements and hollow cathode electrical characteristics were used to study nitrogen and oxygen plasma surface modification of aluminum and stainless-steel hollow cathodes. It was found that the nitridation and oxidation of these metal cathodes resulted in higher plasma densities, in some cases by more than an order of magnitude, and a wider range of pressure operation. Moreover, it was initially thought that the use of aluminum cathodes would not be practical for gas plasma applications, as aluminum is extremely soft and susceptible to sputtering; however, it was found that oxide and nitride modification of the surface could protect the cathodes from such problems, possibly making them viable.

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Surface and optical properties of indium-rich InGaN layers grown on sapphire by migration-enhanced plasma assisted metal organic chemical vapor deposition

Cited by 4 publications

References 39 publications

Electrostatic Stabilization of Nano Liquid Metals in Doped Nonpolar Liquids

Electrostatic Stabilization of Nano Liquid Metals in Doped Nonpolar Liquids

Optical and structural properties of AlN thin films deposited on different faces of sapphire substrates

Recent Advances in Hollow Cathode Technology for Plasma-Enhanced ALD—Plasma Surface Modifications for Aluminum and Stainless-Steel Cathodes

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