Reduction and Patterning of Graphene Oxide and Its Electrode Application for Organic Field Effect Transistor

• Main Authors: Chung-Kai Chang, 張忠凱
• Other Authors: Jeng-Rong Ho
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/03939686891571301461

碩士 === 國立中正大學 === 機械工程所 === 98 === This thesis aims to study fabrication and patterning of graphene for application as conductive thin films. Single-layered, graphene oxide is first separated from bulk graphite by the method of chemical acidification. It is then solved in deionized water. A graphene oxide thin film can subsequently be formed by the technique of spin coating or titration of the aqueous solution of graphene oxide. The formed thin film is translucent and brown and with wrinkles. The surface unevenness is due to the acidification process that changes the carbon structure from the two-dimensional sp2 into the three-dimensional sp3. The oxidized graphene is usually reduced by high-temperature baking. Here in this study, a new process using CO2 laser irradiation is proposed. The surface smoothness can be restored on the reduced graphene film after laser irradiation. However, due to the unevenness of energy absorption, there are still observable wrinkles in the edge region of the laser spot. The reduced graphene is served as an electrode for a polymeric thin-film field-effect transistor. Device characterization demonstrates the mobilities for the transistors using the graphene electrodes reduced from high-temperature baking and CO2 laser irradiation are 8.52 × 10-4 cm2/Vs and 5.10 × 10-4 cm2/Vs, respectively. Finally, a top-gate polymeric thin-film transistor that using CO2 laser for simultaneously reducing graphene oxide as well as patterning the source and drain electrodes is fabricated. The mobility of this transistor is up to 6.37 × 10-3 cm2 / Vs that is close to the performance reported in the literature [1] where the graphene electrodes were reduced from baking at 600oC for half hour with a heating rate of 2 ℃min-1. Besides its excellent ability in patterning, the laser reduction can be executed in the ambient environment and at room temperature.