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

Authors


  • This work was supported by the National Research Laboratory Program and ERC Program (R11-2003-006-03005-0) of the MOST/KOSEF, a grant (F0004022) from Information Display R&D Center under the 21st Century Frontier R&D Program and the Regional Technology Innovation Program (RT104-01-04) of the MOCIE, and the BK21 Program of the Ministry of Education and Human Resources Development of Korea, and the Pohang Acceleratory Laboratory for providing the synchrotron radiation source at the 4C2, 3C2, and 8C1 beam lines used in this study.

Abstract

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 Å s–1) and two-step (first layer 10 nm: 0.1 Å s–1, second layer 40 nm: 4.0 Å 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 cm2 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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