Augel, L.L.AugelBerkmann, F.F.BerkmannLatta, DanielDanielLattaFischer, I.A.I.A.FischerBechler, S.S.BechlerElogail, Y.Y.ElogailKostecki, K.K.KosteckiPotje-Kamloth, KarinKarinPotje-KamlothSchulze, J.J.Schulze2022-03-052022-03-052017https://publica.fraunhofer.de/handle/publica/25093910.1007/s10404-017-2007-3Vertical optofluidic biosensors based on refractive index sensing promise highest sensitivities at smallest area footprint. Nevertheless, when it comes to large-scale fabrication and application of such sensors, cheap and robust platforms for sample preparation and supply are needed-not to mention the expected ease of use in application. We present an optofluidic sensor system using a cyclic olefin copolymer microfluidic chip as carrier and feeding supply for a complementary metal-oxide-semiconductor compatibly fabricated Ge PIN photodetector. Whereas typically only passive components of a sensor are located within the microfluidic channel, here the active device is directly exposed to the fluid, enabling top-illumination. The capability for detecting different refractive indices was verified by different fluids with subsequent recording of the optical responsivity. All components excel in their capability to be transferred to large-scale fabrication and further integration of microfluidic and sensing systems. The photodetector itself is intended to serve as a platform for further sophisticated collinear sensing approaches.enCMOSGe photodiodelarge-scale fabricationcolinear sensingmicrofluidicOptofluidic660journal article