Enhancement of Interconnectivity in the Channels of Pentacene Thin‐Film Transistors and Its Effect on Field‐Effect Mobility

With the aim of improving the field-effect mobility of transistors by promoting the interconnectivity of the grains in pentacene thin films, deposition conditions of the pentacene molecules using one-step (total thickness of layer 50 nm: 0.1 A s -1 ) and two-step (first layer 10 nm: 0.1 A s -1 , second layer 40 nm: 4.0 A s -1 ) depositions are controlled. Significantly, it is found that the continuities of the pentacene thin films vary with the deposition conditions of the pentacene molecules. Specifically, a smaller number of voids is observed at the interface for the two-step deposition, which results in field-effect mobilities as high as 1.2 cm 2 V -1 s -1 ; these are higher by more than a factor of two than those of the pentacene films deposited in one step. This remarkable increase in field-effect mobility is due in particular to the interconnectivity of the pentacene grains near the insulator substrate.

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