Time variation of GaN photoelectrochemical reactions affected by light intensity and applied bias

Koike, Kayo; Sato, Keiichi; Fujii, K.; Goto, T.; Yao, Takafumi

doi:10.1002/pssc.200983450

Cited by 11 publications

(9 citation statements)

References 12 publications

(12 reference statements)

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“…The illumination from the Xe lamp was from 270 to 280 mW/cm 2 at the sample surface. The light intensity was relatively high compared with the intensity of sunlight (about 100 mW/cm 2 ) in order to accelerate the time dependence of the photoelectrochemical processes …”

Section: Methodsmentioning

confidence: 99%

“…The light intensity was relatively high compared with the intensity of sunlight (about 100 mW/cm 2 ) in order to accelerate the time dependence of the photoelectrochemical processes. 17 Photoluminescence was mainly used for the ex situ luminescent recombination evaluation of the GaN photoilluminated surface before and after the photoelectrochemical reaction. Also, in situ evaluations were made during the reaction.…”

Section: Methodsmentioning

confidence: 99%

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Carrier Pathway for Photoelectrochemical Water Oxidation with Intermediate State in n-type GaN Compared with Route of Anodic Corrosion

et al. 2021

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Photoelectrochemical water splitting is a solar-to-chemical energy conversion technique. However, when n-type nonoxide semiconductors are used as photoanodes, they corrode, which is a competitive reaction with water oxidation. To evaluate these competing reactions, the optical properties (photoluminescence) of n-type GaN were examined and compared with the results of a photoelectrochemical analysis. The intermediate hole trap state associated with the yellow luminescence of GaN was found to be a candidate for the carrier transfer site for water oxidation. The hole for electrode corrosion was estimated to have a different pathway from this trap site and to be associated with the hole located at the valence band edge.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Carrier Pathway for Photoelectrochemical Water Oxidation with Intermediate State in n-type GaN Compared with Route of Anodic Corrosion

et al. 2021

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“…The illumination was Xelamp and from 270 to 280 mW/cm 2 in NaOH electrolyte. The light intensity was relatively high compared to the intensity of sunlight (about 100 mW/cm 2 ) in order to accelerate the time dependence of the photocurrent density [3]. The electron and hole concentrations by light illumination were estimated about 2 × 10 16 cm -3 (with assumption of 5% illuminated light with 3.5 eV energy absorbed by GaN).…”

Section: Methodsmentioning

confidence: 99%

“…The other way is to achieve a stable photo-illuminated n-type GaN working electrode as we have studied. The photocurrent time dependence is accelerated by the increasing of illuminated light intensity and is changed by applied bias [3]. Change of the surface index from (0001) due to the surface photocorrosion was clarified to cause the decreasing of photocurrent [4].…”

mentioning

confidence: 98%

Time dependence of water‐reducing photocurrent with change of the characteristics of n‐type GaN photo‐illuminated working electrodes

Fujii

Koike

Atsumi

et al. 2011

Phys. Status Solidi C

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Nitride semiconductors are expected for the working electrodes of photoelectrochemical water splitting due to the chemical stability and band‐gap configuration. The p‐type nitrides are stable under photoelectrochemical conditions but the efficiency of light to hydrogen energy is low. The n‐type nitrides have relatively high energy‐conversion especially for the quantum efficiency, but the photoelectrochemical reaction is not stable because of the anodic photocorrosion. In this article, the relationships between the characteristics of n‐type GaN and the photocurrent stability are discussed. The amount of Si doping was clarified to relate to the stability. The suitable properties for stable photocurrent were different from those for high energy‐conversion efficiency at initial stage. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…However, the stability is not enough under the photoelectrochemical reactions. The surface anodic corrosion is observed due to the existence of high-energy holes at the electrode surface [5,6]. The stability was reported to depend on the electrolyte [7,8].…”

Section: Introductionmentioning

confidence: 98%

Surface Stabilities of n-type GaN Dependent on Electrolyte under Photoelectrochemical Reactions

et al. 2014

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The n-type GaN has stability problem of the surface anodic corrosion during the photoelectrochemical reaction for H 2 generation. The photoelectrochemical surface stabilities of n-type GaN dependent on the electrolytes were investigated. The flatband potential in HCl obtained from Mott-Schottky plot shifted 0.1 V to positive direction compared with that in H 2 SO 4 . The variation of saturated photocurrent of 1 to 3 cycles in H 2 SO 4 was much larger than that of HCl, NaOH and KOH. The surface morphologies also changed by the electrolytes. These results show the absorbed materials on the GaN electrode surface during the photoelectrochemical reactions were changed by the electrolyte and affected the surface reactions.

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Time variation of GaN photoelectrochemical reactions affected by light intensity and applied bias

Cited by 11 publications

References 12 publications

Carrier Pathway for Photoelectrochemical Water Oxidation with Intermediate State in n-type GaN Compared with Route of Anodic Corrosion

Carrier Pathway for Photoelectrochemical Water Oxidation with Intermediate State in n-type GaN Compared with Route of Anodic Corrosion

Time dependence of water‐reducing photocurrent with change of the characteristics of n‐type GaN photo‐illuminated working electrodes

Surface Stabilities of n-type GaN Dependent on Electrolyte under Photoelectrochemical Reactions

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