Ultrastable Zn₃N₂ Thin Films via Integration of Amorphous GaN Protection Layers

Zinc nitride (Zn₃N₂) is a promising semiconductor for a range of optoelectronic and energy conversion applications, offering a direct bandgap of 1.0 eV, large carrier mobilities, and abundant constituent elements. However, the material is prone to bulk oxidation in ambient environments, which has thus far impeded its practical deployment. While previous approaches have focused on stabilizing the material via integration of ZnO surface layers, these strategies introduce additional challenges regarding elevated processing temperatures and limited control of interface properties. In this study, it is shown that amorphous GaN thin films can serve as highly stable protection layers on Zn₃N₂ surfaces and can be deposited at the same growth temperature and in the same deposition system as the underlying semiconductor. The GaN-capped Zn₃N₂ structures exhibit long-term stability, surviving over 3 years of exposure to ambient conditions with no discernible alterations in composition, structure, or electrical properties. Notably, the amorphous GaN coatings can even impede Zn₃N₂ oxidation under prolonged aqueous exposure. Thus, this study offers a solution to stabilize Zn₃N₂ in ambient conditions, providing a viable pathway to its utilization in robust and high-performance electronic devices, such as thin film transistors and solar energy conversion systems.