The phase stability of InP(001) surfaces upon oxygen exposure from first principles

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• III-V semiconductors like indium phosphide (InP) are vital for photoelectrochemical devices, particularly for solar water splitting.
• Electrochemical conditions in aqueous electrolytes can alter InP surface structure and stoichiometry, impacting electronic properties and material stability.
• Understanding surface reconstructions is key to developing effective passivation strategies for InP in electrochemical environments.

Purpose of the Study:

• To investigate the effect of oxygen adsorption on the surface reconstructions of InP(001).
• To identify stable surface structures under various oxygen and indium chemical potentials.
• To provide insights into surface passivation for improved photoelectrochemical device performance.

Main Methods:

• Utilized first-principle calculations to simulate and analyze surface reconstructions.
• Assessed the stability of different InP(001) surface structures under varying chemical potentials.
• Focused on the role of oxygen adsorption in surface modification.

Main Results:

• Predominantly phosphorus-rich InP(001) surfaces were observed across a wide range of indium and oxygen chemical potentials.
• Formation of P-O-type polyphosphate motifs was identified as a common surface structure.
• The commonly assumed indium-rich (2 × 4) mixed-dimer surface reconstruction was found to be unstable under relevant oxygen chemical potentials.

Conclusions:

• Oxygen adsorption significantly influences InP(001) surface reconstructions, favoring phosphorus-rich configurations.
• The instability of In-rich reconstructions under oxygen suggests alternative surface passivation strategies are needed.
• Findings are critical for designing stable and efficient InP-based photoelectrochemical systems for solar water splitting.