Modified Metal Oxide Nanostructure Deposited Semiconductor Interfaces: Tuning the Lewis Acidity of Reversibly Interacting Sites

摘要

We study the reversible response matrices formed at room temperature as metal oxide nanostructure decorated interfaces are modified through in-situ nitridation. Nanostructured TiO_2, SnO_x, NiO, and Cu_xO (x = 1,2), in order of decreasing Lewis acidity, are deposited to an n-type nanopore coated microporous porous silicon interface to direct a dominant electron transduction process for reversible chemical sensing in the absence of significant chemical bond formation. The in-situ modification of the metal oxides deposited to the interface changes the reversible interaction with the analytes NH_3 and NO. The changes of the responses to the analyte are predictable within the framework of the Inverse Hard/Soft Acid/Base model. The trends are characterized by XPS measurements of the shift in the binding energy from that of the oxides and by infrared spectroscopy. Thus, nitridation significantly changes the response matrix for a given gas and creates a distinct new family of response matrices.