Favorable band alignment for photocatalysis at the strontium germanate interface with silicon

TL;DR

This study uses first-principles calculations to analyze the band alignment at the interface of strontium germanate and silicon, showing it is suitable for photocathode applications in photocatalytic water splitting.

Contribution

It provides a detailed first-principles analysis of the band offsets at the SrGeO3/Si interface, demonstrating its potential for photocatalytic use.

Findings

Type-III band alignment at the interface

Favorable electronic structure for photocathode application

Confirmed band offsets with density of states analysis

Abstract

Photocatalytic water splitting is a promising strategy for large-scale clean energy production. However, efficient and low-cost solid-state photocatalysts are still lacking. We present here first-principles calculations to investigate the suitability as photocathode of an epitaxial layer of strontium germanate on a Si(100) single crystal. Conduction and valence bands offsets at the interface between these two semiconductors were determined using state-of-the-art approximations of density functional theory for the accurate prediction of band alignments. The resulting type-III band line-up is also confirmed by inspection of the spatially resolved density of states. It is concluded that the electronic structure of the investigated heterostructure is favorable for photocathodic functionality.