Investigation of surface morphology of n‐type GaN after photoelectrochemical reaction in various solutions for H<sub>2</sub> gas generation

Fujii, K.; Ito, Takashi; Ono, M.; Iwaki, Yasuhiro; Yao, Takafumi; Ohkawa, Kazuhiro

doi:10.1002/pssc.200674917

Cited by 16 publications

(16 citation statements)

References 7 publications

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“…Anodic oxidation of GaN working electrode is, however, one of problems for stable hydrogen evolution. The model was proposed to be oxidation and dissolution of the Ga into an electrolyte [5]. The oversaturated Ga formed Ga oxides on the GaN surface especially in neutral electrolytes.…”

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confidence: 99%

Improvement of hydrogen generation efficiency using GaN photoelectrochemical reaction in electrolytes with alcohol

Fujii

Nakayama

Sato

et al. 2008

Phys. Status Solidi (c)

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Photoelectrochemical water reduction using n‐type GaN in electrolytes with/without alcohol was investigated. For both cases, hydrogen evolution from counterelectrode was observed without bias. Hydrogen gas amount using 1.0 mol/L NaOH electrolyte with alcohol was approximately double compared to that without alcohol where the total current flow charges are similar at 300 min. The amount of hydrogen evolution was almost coincidence with the amount calculated from the total charge flow. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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confidence: 99%

Improvement of hydrogen generation efficiency using GaN photoelectrochemical reaction in electrolytes with alcohol

Fujii

Nakayama

Sato

et al. 2008

Phys. Status Solidi (c)

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“…Comparing from the previous results [4], the average etching depths were small for these experiments. Thus, the photocurrent would mainly used for water splitting and not for GaN surface etching from this consideration.…”

Section: Contributed Articlementioning

confidence: 53%

“…The surfaces with the other treatments hardly changed chemically. Thus, the mechanisms of the surface roughened and chemically changed after the treatments are thought to be different [4].…”

Section: Contributed Articlementioning

confidence: 99%

“…Depending on the experimental conditions, the GaN surface is not stable. Dissolution and/or chemical reactions of the GaN surface were observed during the photoelectrochemical treatment [4,5]. In order to investigate the GaN surface changes, we introduced photoluminescence (PL) after the photoelectrochemical treatment in this report.…”

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confidence: 98%

“…Since the perfect water splitting was observed by GaN powder, the hydrogen generation is especially thought to be one of the most attracted applications of GaN [3]. However, the reactions of GaN surface have not been fully understood yet [4]. Depending on the experimental conditions, the GaN surface is not stable.…”

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Surface changes by GaN photoelectrochemical treatment using various electrolytes with and without C₂H₅OH

Fujii

Sato

Kato

et al. 2009

Phys. Status Solidi (c)

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The surface changes of n‐type GaN during photoelectrochemical treatment were investigated by not only electrochemical measurement but also photoluminescence (PL). The electrolytes used were H2SO4, Na2SO4, and NaOH with and without C2H5OH in order to clarify the reaction difference. The intensity oscillations of deep PL peaks decreased with increasing surface roughness. The D0X peak shift with strain release by the surface roughened were also observed. The surface treated using Na2SO4 with/without C2H5OH were oxidized and caused new PL peaks related to the surface defects. All of the surfaces treated with C2H5OH were observed much less change. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Dodecagonal GaN Microrods: Chemical Stability of a‐, m‐, and c‐Plane Walls and Their Application to Water‐Splitting

Janicki,

Gorantla,

Piskorska‐Hommel

et al. 2024

Adv Materials Inter

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Photoelectrolysis of water is a sustainable option for the production of hydrogen fuel. GaN nano‐ or microstructures are considered for water‐splitting due to their general high chemical stability and high surface‐to‐volume ratio enhancing the process effectiveness. In this study GaN structures with dodecagonal microrods are used as a working electrode for the water‐splitting process. Microrods are grown using a plasma‐assisted molecular beam epitaxy process allowing tailoring of microrod height and density. Their unique property is the of presence twelve sidewalls with alternating a‐ and m‐plane orientations. This enables a simultaneous study of the chemical stability of c‐, a‐, and m‐plane walls of GaN. The water‐splitting process is performed using a 1 mol l−1 NaOH electrolyte solution. Non‐zero current measured at zero bias under illumination indicates that the process takes place. A degradation of the GaN structure is observed after a prolonged process time. In short‐term exposures, etching of microrod sidewalls is observed. Roughening of the a‐plane walls studied by transmission electron microscopy indicates that this orientation is etched with a fastest rate. The internal crystalline structure is not influenced by the etching and remains stable as shown by the X‐ray absorption spectroscopy study.

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Investigation of surface morphology of n‐type GaN after photoelectrochemical reaction in various solutions for H₂ gas generation

Cited by 16 publications

References 7 publications

Improvement of hydrogen generation efficiency using GaN photoelectrochemical reaction in electrolytes with alcohol

Improvement of hydrogen generation efficiency using GaN photoelectrochemical reaction in electrolytes with alcohol

Surface changes by GaN photoelectrochemical treatment using various electrolytes with and without C₂H₅OH

Dodecagonal GaN Microrods: Chemical Stability of a‐, m‐, and c‐Plane Walls and Their Application to Water‐Splitting

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Investigation of surface morphology of n‐type GaN after photoelectrochemical reaction in various solutions for H2 gas generation

Cited by 16 publications

References 7 publications

Improvement of hydrogen generation efficiency using GaN photoelectrochemical reaction in electrolytes with alcohol

Improvement of hydrogen generation efficiency using GaN photoelectrochemical reaction in electrolytes with alcohol

Surface changes by GaN photoelectrochemical treatment using various electrolytes with and without C2H5OH

Dodecagonal GaN Microrods: Chemical Stability of a‐, m‐, and c‐Plane Walls and Their Application to Water‐Splitting

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Investigation of surface morphology of n‐type GaN after photoelectrochemical reaction in various solutions for H₂ gas generation

Surface changes by GaN photoelectrochemical treatment using various electrolytes with and without C₂H₅OH