Novel Insights into Surface Energies and Enhanced Gas-Sensing Capabilities of ZnGa2O4(111) via Ab Initio Studies.

Abstract

This study investigates the surface energies and work function changes in ZnGa₂O₄(111) surfaces with different atomic terminations using ab initio density functional theory. It explores the interactions of gas molecules such as NO, NO₂, and CH₃COCH₃ with Ga-terminated, O-terminated, and Ga-Zn-O-terminated surfaces. This study reveals previously unreported insights into how O-terminated surfaces exhibit enhanced reactivity with NO, resulting in significant work function changes of +6.42 eV. In contrast, Ga-terminated surfaces demonstrate novel interactions with oxidizing gases, particularly NO₂, with a notable reduction in work function change of -1.63 eV, offering potential gas sensor technology advancements. Particularly notable is the Ga-Zn-O-terminated surface, which presents mixed characteristics influenced by the interplay of oxygen and metallic elements (gallium and zinc), leading to substantial work function changes of +4.97 eV for NO and +1.82 eV for NO₂, thereby significantly enhancing sensitivity. This study unveils the previously unexplored roles of Ga-Zn-O-terminated ZnGa₂O₄ surfaces in optimizing semiconductor-based gas sensors, offering both oxidative and reductive potentials and making them versatile for diverse applications.