TitleEffects of ultraviolet illumination and a parylene-A activation layer on the gas phase sensing characteristics of ZnO nanobridges
Publication TypeThesis
Year of Publication2011
AuthorsMason, AD
UniversityOregon State University
CityCorvallis, Or.
Thesis TypeMasters Thesis

ZnO nanowires (NWs) are good candidates for chemical sensing because of their high surface-to-volume ratio. In this work, ZnO nanobridge sensors were fabricated utilizing a novel method which uses carbonized photoresist (C-PR) as a nucleation layer. The use of C-PR allows simultaneous growth and integration of NWs to lithographically-defined features. The nanobridge sensors are shown to be sensitive to the presence of O2, H2O, CO, and H2/N2 gas. However, since ZnO dissolves in water, a protective layer is necessary for these sensors to be used in the liquid or vapor phase. A chemical vapor deposition (CVD) process for amino-[2,2]paracyclophane (parylene-A) was developed and used to successfully protect the NWs. Gas sensing measurements were performed on bare and parylene-A coated devices with and without UV illumination. The parylene-A layer was found to attenuate sensitivity to O2 and H2O, and UV illumination was found to decrease the response time.