Date of Award


Degree Type


Degree Name

Master of Engineering Science


Mechanical and Materials Engineering


T.K. Sham

Second Advisor

Andy Sun


The purpose of this work has been to gain a better understanding the synthesis methodology, structure and properties of SnO2 nanowires and to investigate the influence of substrate on nanowire growth using conventional characterization techniques, such as electron microscopy and X-ray powder diffraction, as well as relatively recent spectroscopic techniques using synchrotron radiation generated soft X-rays. In this thesis a detailed description of the synthesis procedure is provided. A brief description of characterization methods including SEM, TEM, EDX, and XRD is given and a detailed description of Synchrotron radiation and X-ray Absorption Spectroscopy (XAS) is also given. SnO2 nanowires were synthesized using a repeatable and tunable chemical vapor deposition method. Nanowire diameter can be controlled using a combination of reaction temperature and duration. Nanowires were grown on different substrates including Si(100), Carbon paper, TiO2 (100), (110) and (001) and were shown to exhibit apparent preferential growth orientations on the TiO2 substrates. This occurred both in orienting the growth to certain preferred angles with respect to the substrate as well as preferred growth directions of the nanowire crystal. Synchrotron X-ray Absorption Spectroscopy has been used to probe both the electronic and optical properties of the SnO2 nanowires prepared in this study. Peak assignments have been made where possible and discussion of the origin of features. The results confirm the presence of surface states which may be related to the crystallinity of the nanowires. These states are important to the performance of SnO2 as a sensor. In addition, we also find that the electronic structure does not vary considerably despite a clearly noticeable change in the morphology. The presence of defect states observed in the XANES is also confirmed by the observation of green luminescence from these samples.



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