Novel ZnO Nanorod Flexible Strain Sensor and Strain Driving Transistor with an Ultrahigh 107 Scale On-Oft Ratio Fabricated by a Single-Step Hydrothermal Reaction

Novel strain sensor based on ZnO bridging nanorods has been fabricated on Kapton substrate by a single-step hydrothermal reaction, and fully packaged by a polydimethylsioxane layer. Via introducing a metastable contact that can be controlled by strain, flexible strain sensors with high sensitivity and a strain driving transistor with an ultrahigh 10(7) scale on-off' ratio have been demonstrated. However, high performance devices only come from the samples fabricated with lower nutrient solution concentration and are only sensitive to tensile strain. We found out that the response behavior strongly depends on the device structure. The I-V characteristic is highly sensitive to strain due to the change in Schottky barrier height, as well as the change of contact area between ZnO bridging nanorods induced by the metastable morphology under strain.