| AVS 61st International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS+NS-TuA |
| Session: | Nanostructures: Growth, Reactivity and Catalysis |
| Presenter: | Erin Stuckert, Colorado State University |
| Authors: | E.P. Stuckert, Colorado State University E.R. Fisher, Colorado State University |
| Correspondent: | Click to Email |
Tin oxide (SnO2) is an excellent material for gas sensing applications. The sensing mechanism of SnO2 is controlled through gas interactions with adsorbed oxygen, which alters the charge flow through the sensing material. By measuring changes in charge flow, sensitivity and selectivity of a gas sensor can be determined. Sensitivity is improved by increasing surface-gas interactions of high surface area materials, SnO2 nanoparticles and nanowires, combined with surface modification. One surface modification method that can achieve greater oxygen adsorption is plasma treatment; with an expansive parameter space, plasmas allow for greater control of the modification process. In this work, commercial SnO2 nanoparticles and chemical vapor deposition (CVD)-grown SnO2 nanowires were plasma modified to create oxygen vacancies with the aim of increasing oxygen adsorption during sensing. Specifically, we employed Ar/O2 and H2O plasmas because they can etch materials like SnO2 to increase oxygen adsorption by creating surface oxygen vacancies. Ar/O2 plasma treatment of SnO2 nanoparticles and nanowires showed increasing oxygen adsorption with increasing plasma power and treatment time without changing Sn oxidation state or morphology, as measured by X-ray photoelectron spectroscopy (XPS) and powder X-ray diffraction (PXRD). With low power H2O plasma treatments, however, greater oxygen adsorption was observed with nearly complete Sn reduction as well as significant morphological changes evidenced in XPS, PXRD, and scanning electron microscopy (SEM). Plasma treated materials were evaluated for their sensitivity and selectivity for a variety of gases including ethanol, formaldehyde, and benzene. Results for both Ar/O2 and H2O plasma treated SnO2 nanoparticles and nanowires will be presented and discussed with respect to their sensing capabilities, including changes in selectivity and sensitivity.
Keywords:
Plasma treatment
Gas sensor
Tin oxide
Nanowire
Nanoparticle