Strong Green Photoluminescence in Zr3N4 Thin Films with an Orthorhombic Structure

• Published in: Journal of physical chemistry. C 2023-03, Vol.127 (11), p.5561-5566
• Main Authors: Liu, Yuhe, Ge, Nina, Wang, Kunlun, Li, Niannian, Sun, Hui, Pierson, Jean-Francois, Dai, Bo, Wang, Yong
• Format: Article
• Language: English
• Subjects: C: Physical Properties of Materials and Interfaces
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.2c08623

Green light causes the maximum luminous sensation in human eyes, which has many advantages for potential uses. However, the efficiency of light-emitting diodes (LEDs) in the green wavelength range (495–570 nm) is much lower than that in the red or blue region, which is known as the “green gap” problem. In this study, we report the strong green photoluminescence in metastable Zr3N4 thin films with an orthorhombic structure for the first time. Crystallized Zr3N4 thin films have been successfully grown by high-power impulse magnetron sputtering. Notable green photoluminescence in the wavelength region of 490–535 nm has been identified in such orthorhombic Zr3N4 thin films even at room temperature. In addition, a joint experimental and theoretical study has been performed to investigate its electronic structures and to reveal the origins of such green light emissions. The calculations of the transition dipole moments demonstrate that the direct transition between the conduction band minimum and the energy level II below the valence band maximum is responsible for such strong green photoluminescence. This work may pave a new way to solve the “green gap” problem in LEDs with low cost.