Design and Fabrication of Tb $^{3+}$-Doped Silicon Oxy-Nitride Microdisk for Biosensor Applications

We report on fabricating Tb-doped SiON microdisks on a Si chip for low-cost all-Si biosensor applications. The 120-nm-thin 10-μm diameter pedestal-type microdisks were designed and fabricated for optimum biosensing capabilities. Whispering gallery modes of fabricated microdisks were measured via UV top pumping and side-photoluminescence (PL) measurement, and Q-factors of several hundreds were obtained. Using the microdisk resonators to sense streptavidin using biotin functionalization is also demonstrated.