Role of Surface Physical and Chemical Properties in Antibacterial Action of β-Ga₂O₃ and GaOOH

β-Ga₂O₃ is a material showing great promise for numerous applications in sensing, energy storage and high-frequency electronics. Gallium oxide advantageous properties extend to biomedical functions due to its demonstrated cytotoxicity. Despite the significant usefulness of this material, uncertainty surrounding the fundamental mechanisms of the observed behaviors limits the full realization of its potential. In the antibacterial action domain there is a notable lack of research on the β-Ga₂O₃ synthesis precursor – gallium oxyhydroxide (GaOOH) – which is more scalable in production and not requiring high growth temperatures. Elucidation of interactions with bacteria as well as insight into fundamental material properties requires thorough characterization of both material properties and performance in biological assays. In our work, GaOOH microcrystals are synthesized via a hydrothermal method and then undergo high-temperature calcination to produce β-Ga₂O₃. Spectroscopic characterization of the grown materials chemical and morphological properties is performed pre- and post-calcination, as well as pre- and post-growth inhibition assays with the Staphylococcus aureus bacteria. Additionally, time- and energy-dependent surface photovoltage experiments are employed both before and after remote plasma treatment as a means to monitor the surface-specific electronic structure and charge dynamics. Our results reveal insights into the fundamental physical and chemical processes driving the observed cytotoxicity of the studied materials.