Sputtered AlN/Al2O3 distributed Bragg reflectors on amorphous glass

With the sharp increase in the demand for vertical-cavity surface-emitting lasers (VCSELs), the need for high-performance and rapid thermal dissipation distributed Bragg reflectors (DBRs) has become significantly urgent in photonic and optoelectronic devices. In this work, a novel DBR composed of alternating aluminum nitride (AlN) and alumina (Al₂O₃) has been designed and prepared on an amorphous sodium silicate glass substrate via radio frequency (RF) sputtering technique. The effect of a number of stacks on the reflectance of DBRs has been explored theoretically and experimentally. The results show that AlN/Al₂O₃ DBRs with 11.5 pairs can achieve 96 % of reflectance. The stopband bandwidth covers from 720 to 880 nm. The surface roughness is around 2.9 nm with an area of 9 μm². Our sputtering-grown AlN/Al₂O₃ DBR with high reflectance and low surface roughness has laid a good foundation for the potential application of high-performance and rapid thermal dissipation DBRs in photonic integrated circuits.