Datensatz

Zusammenfassung

The operation principles of acoustic wave sensors for liquids are summarized and results are reported on the use of ZX-LiNbO3 acoustic plate mode (APM) devices as detectors for dilute electrolyte and metal ion solutions. The APM is a slow shear wave having a relatively strong acousto-ionic interaction, and thus allows to measure the liquid electrical properties by the perturbation of the wave propagation characteristics. To utilize the APM device as a selective chemical sensor for liquids, the surface is derivatized in order to covalently couple a chemical selective film onto it. For the development of a selective sensor, the surface cleaning and derivatization of the LiNbO3 surface proved to be a major obstacle. We will summarize our recent results on the derivatization of LiNbO3 with alkylaminosilanes. To understand the relationship between the state of the oxide substrate surface and the homogeneity and structural aspects of aminosilane monolayers further, model experiments with different aminosilanes on a Si(100) surface covered with a native oxide layer are described.