Low operating voltage n-channel organic field effect transistors using lithium fluoride/PMMA bilayer gate dielectric

• Alternative to chemically crosslinking of PMMA to achieve low leakage in provided.
• Effect of LiF in reducing gate leakage through the OFET device is studied.
• Effect of gate leakage on transistor performance has been investigated.
• Low voltage operable and low temperature processed n-channel OFETs were fabricated.

We report low temperature processed, low voltage operable n-channel organic field effect transistors (OFETs) using N,N′-Dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) organic semiconductor and poly(methylmethacrylate) (PMMA)/lithium fluoride (LiF) bilayer gate dielectric. We have studied the role of LiF buffer dielectric in effectively reducing the gate leakage through the device and thus obtaining superior performance in contrast to the single layer PMMA dielectric devices. The bilayer OFET devices had a low threshold voltage (Vt) of the order of 5.3 V. The typical values of saturation electron mobility (μs), on/off ratio and inverse sub-threshold slope (S) for the range of devices made were estimated to be 2.8 × 10−3 cm2/V s, 385, and 3.8 V/decade respectively. Our work thus provides a potential substitution for much complicated process of chemically crosslinking PMMA to achieve low leakage, high capacitance, and thus low operating voltage OFETs.

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