Lattice-aligned gallium oxynitride nanolayer for GaN surface enhancement and function extension

TL;DR

This paper presents a novel in-situ process to convert GaN surfaces into a stable gallium oxynitride nanolayer, enhancing device stability and enabling new GaN-based applications.

Contribution

It introduces a two-step oxidation-reconfiguration method to create a metastable GaON nanolayer with improved properties for surface reinforcement.

Findings

GaON nanolayer has wide bandgap and high stability.

Enhanced valence band offset improves device performance.

GaON enables new applications in electronics and photoelectrics.

Abstract

Gallium nitride (GaN), as a promising alternative semiconductor to silicon, is of well-established use in photoelectronic and electronic technology. However, the vulnerable GaN surface has been a critical restriction that hinders the development of GaN-based devices, especially regarding device stability and reliability. Here, we overcome this challenge by converting the GaN surface into a gallium oxynitride (GaON) epitaxial nanolayer through an in-situ two-step "oxidation-reconfiguration" process. The oxygen plasma treatment overcomes the chemical inertness of the GaN surface, and the sequential thermal annealing manipulates the kinetic-thermodynamic reaction pathways to create a metastable GaON nanolayer with wurtzite lattice. This GaN-derived GaON nanolayer is a tailored structure for surface reinforcement and possesses several advantages, including wide bandgap, high thermodynamic stability, and large valence band offset with GaN substrate. These enhanced physical properties can be further leveraged to enable GaN-based applications in new scenarios, such as complementary logic integrated circuits, photoelectrochemical water splitting, and ultraviolet photoelectric conversion, making GaON a versatile functionality extender.