Novel photoelectrochemical behaviors of p-SiC films on Si for solar water splitting

•p-SiC film on p-Si substrate as a photocathode can generate appreciable cathodic photocurrent.•p-SiC film on p-Si substrate as a photoanode also can generate weak anodic photocurrent.•p-SiC film on n-Si substrate can only generate obvious anodic photocurrent.•The dual photocurrent behaviors of p–p structure were investigated and proposed.•No other groups reported such dual photocurrent behaviors of p–p structure.

The electrochemical properties of single-crystalline p-type 3C-SiC films on p-Si and n-Si substrates were investigated as electrodes in H2SO4 aqueous solutions in dark and under light illumination. The photoelectrochemical measurements with different wavelengths of light sources indicate the p-SiC film on p-Si substrate can generate a cathodic photocurrent as a photocathode, which corresponds to hydrogen production, and generate an anodic photocurrent as a photoanode, which corresponds to oxygen evolution. The photocurrent density on wavelength at different potentials for p-SiC on p-Si was investigated. IPCE measurements were addressed to study the photoactive wavelength regimes for the p-SiC film on p-Si and the p-Si. For p-SiC film on n-Si substrate, it can only generate an apparent photocurrent as a photoanode for oxygen evolution. The analyses on anodic and cathodic photocurrent behaviors of the p-SiC on p-Si and the p-SiC on n-Si as electrodes were proposed.