| AVS 62nd International Symposium & Exhibition | |
| Surface Science | Wednesday Sessions |
| Session SS+AS+NS-WeM |
| Session: | Metals, Alloys & Oxides: Reactivity and Catalysis |
| Presenter: | Erin Stuckert, Colorado State University |
| Authors: | E.P. Stuckert, Colorado State University C.J. Miller, Colorado State University E.R. Fisher, Colorado State University |
| Correspondent: | Click to Email |
Although steps have been made to decrease toxic gas emissions globally, these emissions persistently cause detrimental health effects worldwide. Current household gas sensors are limited in their abilities to detect sensitively and selectively at or below relevant toxicity levels for many gases. Tin(IV) oxide (SnO2) nanomaterials are well-equipped to address some of these limitations as a result of dual valency (Sn2+ and Sn4+) and high surface area, thus creating diverse surface chemistry. These properties are advantageous for gas sensing devices because SnO2 functions as a sensor via gas-surface interactions, facilitated by adsorbed oxygen species. By measuring changes in resistance upon gas exposure, sensitivity and selectivity are observed. To increase sensitivity through maximizing gas surface interactions, chemical vapor deposition-grown SnO2 nanowires and commercial nanoparticles were treated with an Ar/O2 and H2O(v) plasma resulting in increased oxygen adsorption. Surface and bulk characterization throughout the plasma treatment process demonstrate an increase in adsorbed oxygen content over a 30 - 150 W applied power range regardless of plasma precursor, in addition to showing that tin reduction occurs upon H2O(v) plasma treatment. Gas sensing performance was initially explored by exposing SnO2 sensors to air at temperatures of 25-300° C to determine base resistance of the materials in an ambient atmosphere. The data show changes in resistance that are dependent upon nanomaterial architecture, plasma treatment conditions, and sensor temperature. Base resistance changes for specific plasma and sensor conditions will be discussed as well as sensor responses and selectivity upon exposure to toxic gases including benzene and carbon monoxide. By combining materials characterization with gas sensor responses, we can optimize sensor sensitivity and selectivity by tuning plasma modification conditions with aims for targeted gas sensing applications.