Title: Synthesis of Ultrathin,Homogeneous Copolymer Dielectrics to Control the Threshold Voltage of OrganicThin-Film Transistors
Author: Kwanyong Pak , Hyejeong Seong , Junhwan Choi , Wan Sik Hwang , and Sung Gap Im*
Journal: Advanced Functional materials, 2016, Vol.26, p.6574–6582
This work demonstrates that thresholdvoltage (VT) of organicthin-fi lm transistors (OTFTs) can be controlled systematically by introducingnew copolymer dielectrics with electropositive functionality. A series ofhomogeneous copolymer dielectrics are polymerized from two monomers,1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane (V3D3) and 1-vinylimidazole(VI), via initiated chemical vapor deposition. The chemical composition of thecopolymer dielectrics is exquisitely controlled to tune the VT of C60 OTFTs.In particular, all the copolymer dielectrics demonstrated in this work exhibitextremely low leakage current densities (lower than 2.5 × 10−8 A cm−2 at ±3 MV cm−1) even with a thickness less than 23nm. Furthermore, by introducing an ultrathin pV3D3 interfacial layer (about 3nm) between the copolymer dielectrics and C60 semiconductor, thehigh mobility of the C60 OTFTs (about 1 cm2 V−1 s−1) remains unperturbed, showing that VT can be controlled independently by tuning thecomposition of the copolymer dielectrics. Coupled with the ultralow dielectricthickness, the independent VTcontrollability allows the VTto be aligned near 0 V with sub-3 V operating voltage, which enables asubstantial decrease of device power consumption. The suggested method can beemployed widely to enhance device performance and reduce power consumption invarious organic integrated circuit applications.