Toward a Dynamically Reconfigurable Pixelated Reflective Display: Focused Ion Beam for Phase-Change Metapixel Structures

The switching and optical properties of phase-change thin films are actively investigated for future smart optical devices. The possibility of having more than one stable state, the large optical contrast between phases, and the fast and reversible switching are some attractive properties driving the research interest. Optical devices based on phase-change alloys are considered the frontier contenders for tunable photonics. The combination of vivid structural color formation, with partial amorphization/crystallization of phase-change alloys, and the associated optical tunability can be integrated into an energy-efficient reflective display device with high pixel density. This work demonstrates a contrast formation due to relative height differences from isolated pixelated structures. A reflective heterostructure device consisting of a low-loss Sb₂Se₃ alloy on a gold substrate is produced. With a focused ion beam, a pixelated metasurface structure is produced. Moreover, the ability to create local height differences using an ion beam is employed to create a structural color combination mimicking traditional light-emitting diodes like red–green–blue pixels. The approach in creating metapixels on phase-change thin film surfaces can open up research interest in phase-change alloys and moving away from semi/static plasmonic systems into truly dynamic display devices is believed.