SiAlON composite films with strengthened chemical intermixing for wide infrared absorption band

Broadband infrared absorbers have been intensively developed in recent decades due to their wide range of applications. Current infrared absorbers usually adapt complicated photonic designs to meet increasing demands, since natural infrared material (e.g., dielectrics, polymers, and metals) can hardly realize broadband and spectrally selective absorption simultaneously. In this paper, a novel infrared absorbing composite SiAlON is proposed and successfully fabricated by co-sputtering Si₃N₄ and AlN. Its wide-band absorption characteristics across through 8 to 16 μm can be tuned simply via adjusting its deposition conditions. The corresponding optical and composition analyses confirm that the broadband features with spectral selectivity are attributed to chemical composition control and the chemical bonding state tunability. This work extends the bandwidth and improves the absorbing flexibility of single material, making a step forward to develop broadband infrared absorbers with simpler structure.