Electrical and optical nanosensors

Electrical and optical nanosensor device platforms for biochemical analytics and biomedical diagnostics have been developed. The nanosensors employ nanobelt, nanogap and photonic wire structures fabricated on silicon-on-insulator (SOI) wafers in order to facilitate CMOS compatible fabrication processing. In SOI wafers, a thin silicon layer is separated by a silicon oxide layer from the bulk. An optimized dry etching process allows the removal of both the top silicon layer and the SiO2 in order to yield the nanobelt and nanowire shapes. The SiO2 layer is finally removed, which results in free standing nanobelts and nanogaps. The optical nanosensors are based on Siphotonic wires and slot-waveguide geometries and incorporate Mach-Zehnder-interferometer structures. Simulation tools for the calculation of the sensitivity and the mode behavior as a function of the waveguide geometry were developed and used in order to optimize the sensing performance.