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Investigation of water splitting using III‐N structures
Author(s) -
Usikov Alexander,
Ermakov Ivan,
Helava Heikki,
Kurin Sergey,
Nikiforov Alexey,
Papchenko Boris,
Puzyk Mike,
Polyakov Alexander,
Lee InHwan,
Makarov Yuri
Publication year - 2017
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201600744
Subject(s) - materials science , nanopillar , electrolyte , sapphire , metalorganic vapour phase epitaxy , optoelectronics , electrode , nanotechnology , chemistry , nanostructure , optics , epitaxy , laser , physics , layer (electronics)
Specifics of the water photoelectrolysis in KOH‐base aqueous solution using GaN‐based structures as working electrodes are studied. The structures were grown by HVPE and MOCVD techniques on sapphire substrates. In highly Si‐doped HVPE‐grown GaN layers ( N D − N A ∼ 3 × 10 18 cm −3 ) a barrier at the E1 offset potential dominates the current–potential ( I – E ) characteristics. The same dominant E1 offset potential was observed in MOCVD‐grown GaN/InGaN nanopillar structures after the treatment. The Debye screening effect in high‐concentration of KOH electrolyte (20–40 wt.%) that reduces the potential barrier was observed clearly in the defectless nanopillar structures. The corrosion process is initiated in the top p‐type layers via channels associated with threading defects and can penetrate deeply into the structure. It further proceeds in a lateral direction in n‐type layers forming voids and cavities in the structure. The H 2 production rate of 0.3–0.6 ml cm −2 h −1 was measured for n‐GaN‐based structure in KOH electrolyte under the Xe‐lamp illumination (concentration factor ×15).