Preparation of Aluminum Oxide Layer for Gate Insulator Application in Organic Thin-Film Transistors

The characteristics of organic thin-films transistors (OTFTs) with the anodized aluminum oxide insulator have been investigated. The OTFT with the barrier-type aluminum oxide insulator exhibited the mobility of 0.09 cm2/Vs, the subthreshold slope of 1.3 V/decade, the threshold voltage of −2.2 V, and the on/off ratio of 7.7 × 104, which are superior to those for the device with the porous-type insulator. The smooth surface of the barrier-type film is found to contribute to a long range hopping of charge carriers in the conducting channel by decreasing the activation energy for the conduction of charge carriers.