High efficiency photoelectrochemical water splitting and hydrogen generation using GaN nanowire photoelectrode

• Published in: Nanotechnology Vol. 24; no. 17; pp. 175401 - 1-5
• Main Authors: AlOtaibi, B, Harati, M, Fan, S, Zhao, S, Nguyen, H P T, Kibria, M G, Mi, Z
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 03.05.2013; Institute of Physics
• Subjects: Arrays; Bias; Cross-disciplinary physics: materials science; rheology; Electrolytes; Exact sciences and technology; Gallium nitrides; Materials science; Nanocomposites; Nanocrystalline materials; Nanomaterials; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanowires; Photoelectric effect; Physics; Quantum wires; Voltage dependence; Doping; Photocurrents; Silicon additions; III-V compound; Bromides; Bending; Illumination; Electrolytes; Nanowires; Photoconductivity; Arrays; Nanostructured materials; Photoelectrode; III-V semiconductors
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/24/17/175401

We have studied the photoelectrochemical properties of both undoped and Si-doped GaN nanowire arrays in 1 mol l−1 solutions of hydrogen bromide and potassium bromide, which were used separately as electrolytes. It is observed that variations of the photocurrent with bias voltage depend strongly on the n-type doping in GaN nanowires in both electrolytes, which are analyzed in the context of GaN surface band bending and its variation with the incorporation of Si-doping. Maximum incident-photon-to-current-conversion efficiencies of ∼15% and 18% are measured for undoped and Si-doped GaN nanowires under ∼350 nm light illumination, respectively. Stable hydrogen generation is also observed at a zero bias potential versus the counter-electrode.