摘要
This work experimentally demonstrates mid-infrared emittance spectra of dielectric and semi-conductor substrates with and without a germanium–antimony–tellurium (GST) film coating. The film experiences non-volatile phase changes at 140°C and 300°C. Impacts from amorphous, face-centered cubic, and hexagonal close packed phases on spectral emittance are demonstrated within the spectral range from 4 µm to 18 µm. The spectra are measured at 100°C, 200°C, 300°C, and 400°C to show temperature dependence. Close-to-total emittance is calculated for comparison. The GST film can reduce emittance from a SiO 2 substrate, but it raises close-to-normal emittance as well as the spectral emittance at wavelengths 5 µm ≤ λ ≤ 18 µm for the doped Si substrate.