Low-voltage p-channel, n-channel and ambipolar organic thin-film transistors based on an ultrathin inorganic/polymer hybrid gate dielectric layer

•Low-voltage operating p-channel, n-channel and ambipolar OTFTs are demonstrated.•The effect of the thickness of pentacene on the device performance is studied.•The effect of the sequence of pentacene/C60 on the device performance is studied.•The high electron and hole mobilities of 3.50 cm2/V s and 0.25 cm2/V s were achieved.

A key issue in research into organic thin-film transistors (OTFTs) is low-voltage operation. In this study, we fabricated low-voltage operating (below 3V) p-channel, n-channel and ambipolar OTFTs based on pentacene or/and C60 as the active layers, respectively, with an ultrathin AlOX/poly(methyl methacrylate co glycidyl methacrylate) (P(MMA–GMA)) hybrid layer as the gate dielectric. Benefited from the enhanced crystallinity of C60 layer and greatly reduced density of electron trapping states at the interface of channel/dielectric due to the insertion of ultrathin pentacene layer between C60 and P(MMA–GMA), high electron mobility can be achieved in present pentacene/C60 heterostructure based ambipolar OTFTs. The effect of the thickness of pentacene layer and the deposition sequence of pentacene and C60 on the device performance of OTFTs was studied. The highest electron mobility of 3.50 cm2/V s and hole mobility of 0.25 cm2/V s were achieved in the ambipolar OTFT with a pentacene (3.0 nm)/C60 (30 nm) heterostructure.

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