Nature of native oxide on GaN surface and its reaction with Al

Prabhakaran, K.; Andersson, T. G.; Nozawa, K.

doi:10.1063/1.117964

Cited by 153 publications

(94 citation statements)

References 2 publications

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“…Similar interactions have been reported by Nozawa et al, where 1.5 ml of aluminum metal reacted with the GaN native oxide forming a surface mixture of Al-metal and aluminum oxide at 200 °C (ref. 19). It is likely that the low sticking coefficient of H 2 O on an oxidized GaN surface promotes this behaviour, that is, the oxygen that terminates the GaN surface is kinetically more available than the oxygen from ambient water.…”

Section: Film Depositionmentioning

confidence: 99%

Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions

et al. 2011

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Property coupling at interfaces between active materials is a rich source of functionality, if defect densities are low, interfaces are smooth and the microstructure is featureless. Conventional synthesis techniques generally fail to achieve this when materials have highly dissimilar structure, symmetry and bond type-precisely when the potential for property engineering is most pronounced. Here we present a general synthesis methodology, involving systematic control of the chemical boundary conditions in situ, by which the crystal habit, and thus growth mode, can be actively engineered. In so doing, we establish the capability for layer-by-layer deposition in systems that otherwise default to island formation and grainy morphology. This technique is demonstrated via atomically smooth {111} calcium oxide films on (0001) gallium nitride. The operative surfactant-based mechanism is verified by temperature-dependent predictions from ab initio thermodynamic calculations. Calcium oxide films with smooth morphology exhibit a three order of magnitude enhancement of insulation resistance.

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Section: Film Depositionmentioning

confidence: 99%

Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions

et al. 2011

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“…However, it is known that Ga oxides are soluble in alkaline solutions. 20,21 Thus it seems impossible that such a natural oxide acts as a stable insulator layer at GaN surfaces in a solution with a wide pH range. There still remains the possibility that the potential at the solution-AlGaN interface is governed by direct adsorption of ions at the given sites of the AlGaN surface.…”

Section: B Ph Response Of the Open-gate Hemtmentioning

confidence: 99%

Liquid-phase sensors using open-gate AlGaN∕GaN high electron mobility transistor structure

Kokawa

Sato

Hasegawa

et al. 2006

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Liquid-phase sensing characteristics of open-gate AlGaN / GaN high electron mobility transistor ͑HEMT͒ structures were investigated in aqueous solutions and polar liquids. In de-ionized water, the open-gate HEMT clearly showed good drain I-V characteristics with current saturation and pinch-off behavior, very similar to I-V characteristics of typical Schottky-gate HEMTs. We observed a fine parallel shift in the transfer curves according to change in the pH value in a solution, indicating the corresponding potential change at the AlGaN surface. The sensitivity for the potential change was 57.5 mV/ pH, very close to the theoretical value of 58.9 mV/ pH at 24°C for the Nernstian response to H + ions. In the low drain bias region, the drain current linearly decreased with the pH value. This also indicated a systematic potential change at the AlGaN surface due to pH change. The present open-gate device showed a fast response to the pH change and a stable operation at fixed pH values. A possible mechanism for the pH response of the AlGaN surface is discussed in terms of equilibrium reactions of hydroxyls at the AlGaN surface with H + in a solution. It was also found that the device was quite sensitive to changes in the electrostatic boundary conditions of the open-gate area by exposure to polar liquids. The drain current linearly decreased with increasing normalized liquid dipole moment.

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“…The binding energy at 531.5 eV can be ascribed to chemisorbed oxygen atoms forming gallium oxides, Ga 2 O 3 , while the higher binding energy is likely due to O-H bonding from OH species. [31][32][33][34][35] (a)…”

Section: Resultsmentioning

confidence: 99%

Fabrication and improvement of nanopillar InGaN / GaN light-emitting diodes using nanosphere lithography

Fadil

Zhan

et al. 2015

J. Nanophoton

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Abstract. Surface-patterning technologies have enabled the improvement of currently existing light-emitting diodes (LEDs) and can be used to overcome the issue of low quantum efficiency of green GaN-based LEDs. We have applied nanosphere lithography to fabricate nanopillars on InGaN∕GaN quantum-well LEDs. By etching through the active region, it is possible to improve both the light extraction efficiency and, in addition, the internal quantum efficiency through the effects of lattice strain relaxation. Nanopillars of different sizes are fabricated and analyzed using Raman spectroscopy. We have shown that nanopillar LEDs can be significantly improved by applying a combination of ion-damage curing techniques, including thermal and acidic treatment, and have analyzed their effects using x-ray photoelectron spectroscopy.

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Nature of native oxide on GaN surface and its reaction with Al

Cited by 153 publications

References 2 publications

Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions

Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions

Liquid-phase sensors using open-gate AlGaN∕GaN high electron mobility transistor structure

Fabrication and improvement of nanopillar InGaN / GaN light-emitting diodes using nanosphere lithography

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