Electrical engineering

Physics

Reversible hydrogen electrode

Fabrication

Pathology

Saturation current

Nanotechnology

Electrode

Current density

Photocatalysis

Semiconductor

Engineering

Catalysis

Voltage

Physical chemistry

Chemistry

Thin film

Materials science

Alternative medicine

Insulator (electricity)

Photocurrent

Reference electrode

Quantum mechanics

Water splitting

Chemical engineering

Optoelectronics

Electrochemistry

Biochemistry

Medicine

Nature Communications

Metal-insulator-semiconductor (MIS) structures are widely used in Si-based solar water-splitting photoelectrodes to protect the Si layer from corrosion. Typically, there is a tradeoff between efficiency and stability when optimizing insulator thickness. Moreover, lithographic patterning is often required for fabricating MIS photoelectrodes. In this study, we demonstrate improved Si-based MIS photoanodes with thick insulating layers fabricated using thin-film reactions to create localized conduction paths through the insulator and electrodeposition to form metal catalyst islands. These fabrication approaches are low-cost and highly scalable, and yield MIS photoanodes with low onset potential, high saturation current density, and excellent stability. By combining this approach with a p + n-Si buried junction, further improved oxygen evolution reaction (OER) performance is achieved with an onset potential of 0.7 V versus reversible hydrogen electrode (RHE) and saturation current density of 32 mA/cm 2 under simulated AM1.5G illumination. Moreover, in stability testing in 1 M KOH aqueous solution, a constant photocurrent density of ~22 mA/cm 2 is maintained at 1.3 V versus RHE for 7 days.

Scalable, highly stable Si-based metal-insulator-semiconductor photoanodes for water oxidation fabricated using thin-film reactions and electrodeposition