Uniform TitleZnO nanotip-based acoustic wave sensors
NameZhang, Zheng (author), Lu, Yicheng (chair), Sheng, Kuang (internal member), Jiang, Wei (internal member), Galoppini, Elena (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectElectrical and Computer Engineering,
Acoustic surface wave devices,
DescriptionZnO nanostructures possess unique advantages for the biosensor applications, such as giant surface areas, high sensitivity, biological compatibility, and integratability with Si-based electronics.
This dissertation addresses the development of ZnO nanotip-based acoustic wave sensors, and their biological applications. ZnO nanostructures are grown on the surfaces of various sensors, including surface acoustic wave (SAW) sensors and quartz crystal microbalance (QCM) sensors, by metalorganic chemical vapor deposition (MOCVD). The single crystalline ZnO nanotips are well aligned along the substrate normal direction, confirmed by scanning electron microscope (SEM) and X-ray diffraction (XRD) measurements, respectively. The photoluminescence (PL) measurements show the free exciton emission at room temperature, indicating superior optical property of the ZnO nanotips.
The surface wetting properties of the ZnO nanostructured sensing surfaces are studied. It is demonstrated that the contact angles on ZnO nanotips can be changed between 0 and 130 degrees. The repeatable and reversible transitions between hydrophobic and superhydrophilic status of ZnO nanostructured surfaces have been achieved by UV illumination and low temperature oxygen annealing. The transition rate has been increased by 10-times in comparison with the published results. The immobilizations of DNA oligonucleotides to ZnO nanostructures have been conducted. DNA hybridization with complementary and non-complementary second strand DNA oligonucleotide is used to study the selectivity of the SAW sensor. The radioactive labeling tests and SAW sensor responses demonstrate that by using ZnO nanotips the DNA immobilization is enhanced by a factor of 200 in comparison with using the ZnO films. A ZnO nanotip-based QCM sensor is developed. The ZnO nanotip coated QCM sensor shows a 10-times larger frequency shift than that of regular QCM sensors, when measuring the same DNA oligonucleotide solution. In addition, the superhydrophilic behaviors of the nanotip array significantly reduce the required liquid volume for effective detection and only 3% solution is required to cover the same sensing surface compared to the traditional QCM sensor. The superhydrophilic sensing surface boosts the solution taking ability; therefore, enhances the sensitivity of the QCM sensor. The functionalization of ZnO nanotips with a series of mono- or bi-functional linkers have been achieved, which makes the selective biological sensing possible on the ZnO nanotip based QCM. ZnO nanotip-based SAW and QCM sensors possess the advantages of both traditional acoustic wave sensors and ZnO nanostructures, including high efficiency, good selectivity, low cost and broad biological applications.
NoteIncludes bibliographical references (p. 150-157).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.