【摘要】 基于相变材料铟锑碲（IST）在类半导体非晶态与类金属晶态间可逆切换且光学性质具备非易失性的特性，将铟（In）、锑（Sb）、碲（Te）纳米粉末按3∶1∶2的质量比混合，并压制成用于磁控溅射的In3SbTe2靶材。在高反射衬底上，通过薄膜沉积、光刻、图案转移等工艺，制备出具有IST微纳圆盘阵列结构的超表面器件，以实现对红外热辐射的动态调控。选取氧化铟锡（ITO）和钨（W）作为反射材料，阐述了器件的结构设计、谐振模式和样品制备方法，并对比分析了实验测试与仿真结果。研究结果表明，ITO-IST与W-IST两种超表面器件均具备多态可调特性。在非晶态下，二者均表现出窄带高辐射特征。在加热晶化过程中，器件逐步相变至一系列中间态，其谐振强度逐渐减弱，最终在完全晶态时表现出宽带低辐射特征。两类器件的中间态热辐射变化趋势存在显著差异：ITO-IST器件的谐振波长逐渐蓝移，而W-IST器件的谐振波长基本保持不变。更多还原

【Abstract】 Objective The dynamic regulation of infrared thermal radiation holds significant applications in fields such as optoelectronic devices, infrared detection, and stealth technology. Combining phase-change materials with micro-nano photonic structures is an effective approach to achieve this type of regulation. As a non-volatile phase-change material, indium-antimony-tellurium（IST） exhibits remarkable differences in optical properties before and after phase transition, thus emerging as a research hotspot in related areas. However, existing radiators based on IST thin films can only switch between two extreme states（amorphous and crystalline）, and the emissivity of different regions within the same intermediate state remains uneven during the phase transition process. Furthermore, IST belongs to the growth-dominated crystallization type of material, and current research on the intermediate states of its photonic devices is relatively scarce. Therefore, this study aims to construct a composite structure consisting of a high-reflectivity substrate and an IST metasurface to realize multi-state tunable infrared thermal radiation, thoroughly investigate the infrared radiation characteristics of IST metasurface devices in amorphous, multiple intermediate, and fully crystalline states, reveal the influence of different reflective layer materials on the evolution law of the device radiation in intermediate states, and provide theoretical and experimental support for the wide application of IST materials in photonic devices.Methods Firstly, In, Sb, and Te nanopowders are mixed at a mass ratio of 3∶1∶2 and pressed to prepare In₃SbTe₂ targets for magnetron sputtering. Subsequently, indium tin oxide（ITO） glass and silicon wafers sputtered with Ti/W layers are selected as high-reflectivity substrates, respectively. Through processes including thin film deposition, ultraviolet lithography, magnetron sputtering of IST, pattern transfer, and sputtering of a SiO₂ protective layer, IST micro-nano disk array metasurface devices（ITO-IST and W-IST） with a period of 5 μm, radius of 2 μm, and height of 600 nm are fabricated. The finite-difference time-domain（FDTD） method is utilized for device structure design, resonance mode analysis, and parameter scanning to explore the regulatory effects of disk period, radius, and height on the resonance wavelength and emissivity. Scanning electron microscope（SEM） is employed to observe the sample morphology（Fig. 4 and Fig. 7）. Thermal stage heating is used to induce the phase transition of IST, and a Fourier transform infrared spectrometer（FTIR） is used in combination to test the reflectance spectra of different phase transition states（amorphous, intermediate, and fully crystalline） for obtaining radiation characteristics. Finally, the experimental results are verified against the FDTD simulation results.Results and Discussions FDTD simulations demonstrate that the amorphous IST metasurface exhibits a narrowband radiation peak at 9.86 μm（first-order magnetic resonance）, whereas the crystalline state shows broadband high-reflectivity characteristics（Fig. 1）. Parameter scanning indicates that the resonance wavelength is hardly modulated by the period, and increases in radius and height can cause a redshift of the resonance wavelength, enabling on-demand regulation of the peak wavelength（Fig. 2）. SEM observations reveal that the device features a steamed bun-shaped disk structure with a higher center and lower surroundings（Fig. 4）. The phase transition test under heating at 255 ℃ shows consistent device characteristics at different positions; during the phase transition process, the resonance wavelength gradually undergoes a blueshift（maximum blueshift of 650 nm）, and the resonance intensity continuously weakens until it disappears（Fig. 5）. For FDTD simulations, a multi-disk stacking model is adopted to simulate the actual structure, and the variation trend of reflectance spectra in the amorphous and intermediate states is basically consistent with the experimental results（Fig. 6）. Crystallization kinetics analysis indicates that this phenomenon originates from the annular growth of crystalline IST from the edge to the interior of the disk. SEM observations confirm that its disk structure is regular（Fig. 7）. The phase transition test under heating at 235 ℃ shows that during the phase transition process, the resonance wavelength remains essentially unchanged, with only a weakening of resonance intensity and broadening of the peak shape, and that the fully crystalline state exhibits broadband high-reflectivity characteristics（Fig. 8）. The simulation results are consistent with the experimental trends, and this characteristic is attributed to the higher thermal conductivity of the W substrate, which allows IST to complete crystallization in a disk-by-disk phase transition mode. Both ITO-IST and W-IST achieve multi-state tunability, but the evolution laws of radiation in intermediate states differ—the resonance wavelength of the former undergoes a blueshift, while that of the latter remains basically unchanged; in addition, the W-IST requires a lower heating temperature and shorter time to complete the phase transition.Conclusions A multi-state tunable thermal radiator based on In₃SbTe₂ metasurface is successfully fabricated. Two distinct radiation regulation modes can be achieved by selecting different high-reflectivity substrates: the ITO-IST device enables the coordinated tuning of resonance wavelength and intensity, making it suitable for multi-level dynamic regulation of infrared thermal radiation; the W-IST device allows intensity tuning at a fixed wavelength, which is applicable to single-wavelength thermal radiation light source scenarios with low monochromaticity requirements. This study confirms that the type of reflective layer material significantly affects the IST phase transition mode and the radiation characteristics of the device intermediate states, and this material can also be extended to other metals such as gold. The systematic analysis of the intermediate state characteristics and phase transition modes of the IST metasurface, as presented in this study, provides new insights for an in-depth understanding of the optical regulation mechanism of growth-dominated phase-change materials, and effectively promotes the application and development of IST in optical structure systems.更多还原