Nowadays there is a growing interest to develop flexible devices that can be used in applications spanning from displays to energy harvesting. This is due to the potential of such devices to be integrated onto various-shaped surfaces and also to be roll-to-roll processed. However, there are still a few challenges to be tackled before their full commercialization. In particular, the direct fabrication of micro/nano-scale functional features on a large-area flexible substrate remains a critical challenge. This is because it requires both low temperature processing and precise control of the feature size. Kathy Sabolsky for all her help in the laboratory and demonstrating how to operate different equipment. Nick Morris for his help in the laboratory, taking SEM images and performing XRD. As well as our discussions about ZnO structures and piezoelectric devices. Undergraduates, Jacob Cordonier and Dillon Carden for their lab work. Finally, Katie and my parents, David and Marian, for all their loving support.