Core–shell photoanode developed by atomic layer deposition of Bi 2 O 3 on Si nanowires for enhanced photoelectrochemical water splitting

Core–shell nanowire (NW) arrays, which feature a vertically aligned n-type Si NW core and a p-type α -Bi 2 O 3 shell, are developed as a highly efficient photoanode that is suitable for water splitting. The morphology and structure of the heterostructure were characterized by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD). The deposition of Bi 2 O 3 nanolayers on the surface of the smooth Si NWs causes the surface of the NWs to become rough. The as-prepared core–shell NW photoelectrode has a relatively low reflectance in the visible light region, suggesting good light absorption. The core–shell NW arrays show greatly improved photoelectrochemical water-splitting performance. Photoelectrochemical stability for over 16 h under constant light illumination and fixed bias potential was...

Baicheng Weng, Fenghua Xu and Jianguang Xu

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