N-type organic thin-film transistor using N,N'-dioctyl-3,4,9,10-perylene tetracarboxylic diimides grown by organic vapor deposition

We have studied the dependence of grain size of n-type organic semiconductor on the electrical performance of n-type organic thin-film transistor (N-OTFT) operated in air. The bottom-contact type N-OTFT based on N,N'-dioctyl-3,4,9,10-perylene tetracarboxylic diimides (PTCDI-C-8), which is unstable in air, is grown by organic vapor deposition to obtain large PTCDI-C-8 grain. Even though PTCDI-C-8 is unstable in air, the field-effect mobility of 5.6 x 10(-3) cm(2)/V sand on/off current ratio of similar to 10(6) were obtained in ambient air. The PTCDI-C-8 layer was patterned by oxygen plasma etching with the passivation layer of parylene-C. In spite of the degradation in the electrical performance, the n-type OTFT still operated in air after the patterning process. These results show the possibility of organic complementary metal-oxide-semiconductor (O-CMOS) devices with large scale integration without shadow mask. (C) 2008 Elsevier B.V. All rights reserved.