Effects of the morphology of inkjet printed zinc oxide (ZnO) on thin film transistor performance and seeded ZnO nanorod growth

In this work, inkjet printing (IJP) of sol-gel precursor ink of zinc oxide (ZnO) has been carried out; with the focus placed on studying the relationship between IJP parameters and pattern morphology. The unique 'coffee ring' morphology, despite often considered as undesirable, was intelligently utilized for improving thin film transistor performance. Furthermore, inkjet printed ZnO patterns were employed as seed layers for hydrothermal growth of ZnO nanorod. The critical influence of 'coffee ring' morphology towards heterogeneous nucleation and crystallization behavior of ZnO nanorod was studied. Different morphologies of ZnO nanorods on specific regions of seed layers were elucidated based on non-uniform surfactant distribution. This work underlines the opportunity of utilizing the unique inkjet printed pattern morphology in fabrication of nano-scale ultra-smooth thin film devices with controlled distribution of variable ink components.