Flexography as manufacturing method for carbon nanotube based thin film transistors

摘要

Large volume implementation of printed electronics requires the development of mass-producible and reliable printedtransistors. In this work, we present the initial development of field-effect devices printed by flexography usingcarbon nanotubes (CNTs) as semiconducting material. CNTs offer a number of advantages over commonly adoptedorganic semiconducting materials, namely high mobility and environmental stability. However their device performancedepends on the accurate deposition of the CNT network. Flexography, with its accurate control of thin filmdeposit, offers the capabilities to address this issue, furthermore as a leading roll-to-roll printing process for packaging,flexography is key to large volume integration.Devices were produced using Multi Walled CNTs as the active layer. A top gate top contact design deviceconfiguration was employed. Flexography was used for printing the source/drain electrodes and CNT layer. Devicecharacterization showed field effect behavior. Two layouts for the electrode, interdigitated and parallel, were testedshowing similar ON/OFF ratios. Current device performance was limited by the high off current characteristic ofMWCNTs; improvements are expected through refinement of CNT semiconductor layer and scale of the device.This work has demonstrated the potential of flexography for manufacturing of TFT structures with CNTs as theactive layer.