Small device-to-device variation of 6,13-bis(triisopropylsilylethynyl)pentacene field-effect transistor arrays fabricated by a flow-coating method

Abstract

Bottom-contact/bottom-gate-type organic field-effect transistor (OFET) arrays have been fabricated using a flow-coating method, and the device-to-device variation has been examined. The flow-coated active layer of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-PEN) was composed of arrays of needle-shaped crystals whose long axes were aligned along the flow-coating direction. By measuring the electrical characteristics of one hundred twenty OFETs with the channel current direction parallel or perpendicular to the flow-coating direction, we evaluated the device-to-device variation in the device properties. The field-effect hole mobilites (average ± standard deviation) for the parallel and perpendicular OFET sets were 0.51 ± 0.03 and 0.12 ± 0.03 cm2·V−1·s−1, respectively. The small standard deviations clearly show the high spatial uniformity of the TIPS-PEN active layer. The much smaller relative standard deviation, a measure of device-to-device variation, for the parallel OFET set (6%) can be attributed to a high degree of alignment of needle-shaped TIPS-PEN crystals along the flow-coating direction.