A high mobility ambipolar field effect transistor using a 2,6-diphenylbenzo[1,2-b:4,5-b ′]diselenophene/fullerene double layer

A high mobility ambipolar field effect transistor (FET) was fabricated using a double-layer structure composed of 2,6-diphenylbenzo[1,2-b:4,5-b′]diselenophene (DPh-BDS) as a p-type layer and fullerene (C60)(C60) as an n-type layer. The FET characteristics showed a large dependence on the DPh-BDS thickness, and excellent ambipolar behavior with the maximum electron and hole mobilities of μe=3.0cm2/V s and μh=0.10cm2/V s was obtained with the optimum DPh-BDS thickness of 10–20 nm. The result indicates that the μeμe of C60C60 was considerably enhanced by keeping it away from the electron traps on the SiO2 surface and by improving the crystalline texture of the C60C60, which was achieved by the underlying DPh-BDS buffer layer having a rather high hole mobility on the SiO2 layer.