Flexible paper transistor made with ZnO-cellulose hybrid nanocomposite for electronic applications

Semiconducting ZnO layer chemically grown on regenerated cellulose and its flexible paper transistor were studied. ZnO layer-cellulose composite was prepared by a simple chemical reaction process which included alkaline hydrolysis at low temperature lower than 100°C and used wet regenerated cellulose as a hydrophilic substrate. By increasing the concentration of ZnO seeding layer on cellulose, the area of ZnO cluster also increases. In the low concentration conditions from 20 mM to 50 mM, it is observed that the average size of ZnO nanorods increases as the seeding concentration increases. However, flower-shaped ZnO structure is observed in higher concentration over 50 mM due to clustering effect during the growth of ZnO rods. Thin ZnO layer composed of nano-rods seemed to be grown well on regenerated cellulose and layer thickness of ZnO was well controlled by reaction time. Structural data of as grown ZnO/cellulose provides the crystal orientation-limited growth mechanism of ZnO nano-rod, which can be controlled by the reaction time of chemical process. Using conventional lift-off process, thin ZnO layer based transistor was fabricated by forming source/drain as well as gate electrode. More detailed ZnO-cellulose based transistor is discussed.