Fabrication of single crystal field-effect transistors with phenacene-type molecules and their excellent transistor characteristics

Single crystal field-effect transistors (FETs) using [6] phenacene and [7] phenacene show p-channel FET characteristics. Field-effect mobilities, mu s, as high as 5.6 x 10 (1) cm(2) V (1) s (1) in a [6] phenacene single crystal FET with an SiO2 gate dielectric and 2.3 cm(2) V (1) s (1) in a [7] phenacene single crystal FET were recorded. In these FETs, 7,7,8,8-tetracyanoquinodimethane (TCNQ) was inserted between the Au source/drain electrodes and the single crystal to reduce hole-injection barrier heights. The mu reached 3.2 cm(2) V (1) s (1) in the [7] phenacene single crystal FET with a Ta2O5 gate dielectric, and a low absolute threshold voltage vertical bar V-TH vertical bar (6.3 V) was observed. Insertion of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F(4)TCNQ) in the interface produced very a high mu value (4.7-6.7 cm(2) V (1) s (1)) in the [7] phenacene single crystal FET, indicating that F(4)TCNQ was better for interface modification than TCNQ. A single crystal electric double-layer FET provided mu as high as 3.8 x 10 (1) cm(2) V (1) s (1) and vertical bar V-TH vertical bar as low as 2.3 V. These results indicate that [6] phenacene and [7] phenacene are promising materials for future practical FET devices, and in addition we suggest that such devices might also provide a research tool to investigate a material's potential as a superconductor and a possible new way to produce the superconducting state. (C) 2013 Elsevier B.V. All rights reserved.