Design principles for III-nitride-nanocluster photocatalysts from region-resolved electronic structure

TL;DR

This study develops design principles for nanocluster cocatalysts on III-nitride semiconductors by analyzing their electronic structure and interfacial electrostatics, aiding the rational design of efficient photocatalytic interfaces.

Contribution

It introduces a region-resolved electronic structure framework and machine learning models to understand and optimize nanocluster-semiconductor interfaces for photocatalysis.

Findings

Nanocluster-covered regions control charge injection and band bending.

Surface states facilitate surface activation in uncovered nitride regions.

Interfacial electrostatics influence cocatalyst effectiveness.

Abstract

Understanding how nanocluster cocatalysts modify the electronic structure of III-nitride surfaces is central to the rational design of efficient photocatalytic interfaces. Here, we establish design principles for nanocluster cocatalysts on GaN-based semiconductors by systematically analyzing the spatially resolved electronic structure of GaN-, InGaN-, and ScGaN-based slabs decorated with six-atom elemental nanoclusters. Using a region-resolved projected local density of states (PLDOS) framework, we reveal that semiconductor-nanocluster interfaces operate as laterally heterogeneous electronic systems, in which nanocluster-covered regions govern charge injection and band bending, while uncovered nitride regions retain surface states that facilitate surface activation. We further show that cocatalyst effectiveness is controlled not only by hydrogen adsorption energy, but also by interfacial electrostatics, including band alignment, metal-induced gap-state suppression, and in-plane dipoles, with the semiconductor substrate defining the baseline electronic regime. Machine-learning regression models trained on physically motivated global and region-specific descriptors quantify the relative importance of these mechanisms and their correlation with hydrogen adsorption energetics. Together, this work provides transferable design principles for nanocluster cocatalysts on III-nitrides and a generalizable first-principles framework for studying spatially heterogeneous semiconductor-nanocluster interfaces.