Evaluation of metal oxide nanowire materials with temperature-controlled microsensor substrates

Nanomaterials are becoming increasingly important for next-generation Chemical sensing devices. In particular, quasi-one-dimensional materials, such as nanowires, are attracting a great deal of interest. While early examples have demonstrated the promise offered by these nanoscale materials, challenges still remain for integration, systematic characterization and evaluation of such materials in operational devices. Here, a means to assess the performance of nanowire- based materials as chemical microsensors is illustrated with two examples. Poly- crystalline nanowire sensing materials are integrated with microsensor substrates that feature an embedded heater, facilitating the use of temperature to interrogate the response characteristics of sensing materials. By changing the operating temperature, different effects are observed as a function of nanowire loading density (aligned tin oxide nanowires) or overall material morphology (tungsten oxide materials, including a thin film). Further, by using conventional signal processing and data analysis approaches, the sensitivity and selectivity of these materials as a function of material scale and morphology are characterized.