Short-Range Order Tunes Optical Properties in Long-Range Disordered ZnSnN2–ZnO Alloy

• Published in: Chemistry of materials Vol. 34; no. 9; pp. 3910 - 3919
• Main Authors: Melamed, Celeste L., Miller, Moira K., Cordell, Jacob, Pucurimay, Linda, Livingood, Alyssa, Schnepf, Rekha R., Pan, Jie, Heinselman, Karen N., Vila, Fernando D., Mis, Allison, Nordlund, Dennis, Levy-Wendt, Ben, Lany, Stephan, Toberer, Eric S., Christensen, Steven T., Tamboli, Adele C.
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10.05.2022; American Chemical Society (ACS)
• Subjects: Absorption,Alloys; Chemical structure; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS,MATERIALS SCIENCE; Diseases and disorders; functional materials; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; local site ordering; MATERIALS SCIENCE; optical absorption; Oxides; semiconductor; short-range ordering
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.1c03938

Local site ordering offers a new paradigm for property control in functional materials. However, systems that exhibit a propensity for local order and global disorder are often challenging to characterize, and demonstrations of ordering-induced property tuning are few and far between. Here, we demonstrate that short-range ordering tunes the optical absorption edge in the long-range disordered alloy system (ZnSnN2)1–x (ZnO)2x at x = 0.25. We use combinatorial cosputtering to synthesize a set of thin-film samples spanning this alloy space. X-ray diffraction demonstrates lattice contraction as a function of alloy composition, confirming that a mixed-anion and -cation alloy has been synthesized. Using N and O K-edge X-ray absorption near-edge structure in conjunction with simulations of cation-disordered supercell structures, we find that samples exhibit octet-rule-breaking motifs around both anions. Upon annealing at an alloy composition of x = 0.25, X-ray absorption analysis suggests that local motif structure shifts toward octet-rule-conserving while long-range disorder is maintained. Spectroscopic ellipsometry reveals that local ordering increases the absorption edge energy at constant composition. Additionally, alloy-induced optical absorption edge tuning is demonstrated. This work paves the way toward property tuning with short-range ordering in (ZnSnN2)1–x (ZnO)2x and beyond.