Sputtering AlN/In_xAl_1-xN distributed Bragg reflector across the full visible range on Si and SiO₂ substrates

III-nitride-based distributed Bragg reflectors (DBRs) are advantageous in being in-situ integrated in III-nitride devices, and the bandgaps and their other corresponding optical parameters are tunable. However, a growing nitride DBR with low strain and high reflectivity remains a challenge. Here we demonstrate an AlN/In_xAl_1-N DBR grown on Si and SiO₂ substrates by reactive radio-frequency magnetron sputtering. Reflectance wavelengths covering the whole visible regions of the visible spectrum were achieved by rationally tuning the indium composition in In_xAl_1-N and each layer's thickness of an AlN/In_xAl_1-N DBR. This Letter should advance the design and fabrication of nitride optical and optoelectrical devices by incorporating an AlN/In_xAl_1-N DBR, such as vertical-cavity surface-emitting laser (VCSEL) and RC LEDs.