Tunable Electromagnetic Performance of Pt–Si–O Films in Mid-Infrared and Microwave Spectrums

Electromagnetic performance regulation in mid-infrared (MIR) and microwave (MW) spectrums is crucially significant, which can be achieved by heterophase introduction and structural manufacturing. In this work, Si-O amorphous phase is introduced into Pt film by magnetron co-sputtering technique, the film thickness is optimized by adjusting deposition time. After annealing treatment, a double-layered structure is constructed with the migration and growth of Pt crystals, in which the lower layer is composed of Pt coarse grains while the upper layer is Si-O amorphous phase with embedded Pt fine grains. Furthermore, due to the thickness difference, diverse kinds of structural patterns (arrays or mesh) can be obtained with the solid-state dewetting of the lower layer. According to the increasing thickness, the infrared emissivity can decrease from 0.67 to 0.25 (8–14 μm), demonstrating a great decline of apparent temperature of 162.9 °C when the background is 300 °C. And the microwave transmissivity also exhibits tremendous variation over 90% (from 96% to 5%), realizing the transformation from transmitting to shielding.