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 ( C 60 ) 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 μ e = 3.0 cm 2 / V s and μ h = 0.10 cm 2 / V s was obtained with the optimum DPh-BDS thickness of 10–20 nm. The result indicates that the μ e of C 60 was considerably enhanced by keeping it away from the electron traps on the SiO2 surface and by improving the crystalline texture of the C 60 , which was achieved by the underlying DPh-BDS buffer layer having a rather high hole mobility on the SiO2 layer.