Sreekanth, K. V., Wu, Q. Y. S., Jana, S., Singh, R., & Teng, J. (2025). Tunable directional thermal emission using a phase change material-based multilayer structure. Nanoscale Horizons, 10(10), 2615–2620. https://doi.org/10.1039/d5nh00367a
Abstract:
The directional and spectral control of thermal emission with a tunable angular range is essential for realizing next-generation smart thermal emitters. However, existing photonic strategy-based thermal emitters manage thermal emission only over a fixed angular range. Here, we present a lossless chalcogenide phase change material (PCM)-based tunable multilayer structure as a thermal emitter for actively regulating angular selectivity in thermal emission. We develop a tunable multilayer stack with a thickness of 1.35 µm by layering alternating thin films of SiO2 and high-crystallization-temperature PCM, such as Sb2S3. The principle underlying the proposed tunable directional control of thermal emission relies on the tunable Brewster mode within the SiO2-Sb2S3 multilayer cavity. For p-polarized light, the cavity exhibits maximum emissivity across a broad spectral band (10-18 µm) around the Brewster angle. In particular, a peak emissivity of over 95% is achieved in this broad spectral band at the Brewster angle. The angular range of maximum thermal emission can be tuned through the non-volatile structural phase transition property of Sb2S3. Moreover, we demonstrate electrically controlled thermal emission using a microheater-integrated Sb2S3-SiO2 multilayer cavity. This photonic structure could serve as a versatile, tunable, lithography-free platform to dynamically control the angular range of directional thermal emission and emissivity for emerging applications of thermal emitters.
License type:
Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Funding Info:
This research / project is supported by the A*STAR - Manufacturing, Trade, and Connectivity Programmatic Fund
Grant Reference no. : M22L1b0110
This research / project is supported by the National Research Foundation - Competitive Research Programme
Grant Reference no. : NRF-CRP26-2021-0004