Recently, it was proposed in the literature that the electron trap<br />on a hydroxyl-containing dielectric interface of an organic field<br />effect transistor (OFET) hinders its n type operation. The authors<br />fabricated pentacene and fullerene OFETs with a hydroxyl-free insulating<br />material, a long-chain alkane, i.e., tetratetracontate (TTC), C44H90<br />layer coated on the SiO2 dielectric layer. The displacement current<br />measurements clearly demonstrated that the electron trap of the SiO2<br />surface is suppressed by the TTC layer. For a pentacene FET with<br />an Al electrode and SiO2 dielectric layer, a p type operation was<br />observed, while the operation mode was switched to the n type by<br />the insertion of TTC on the SiO2 interface. By simple patterning<br />of the TTC layer to produce a bipolar injection, the authors fabricated<br />an ambipolar pentacene FET with a single kind of metal electrode.<br />Thus TTC is a good material for the surface modification of a dielectric<br />layer in OFETs. (c) 2007 American Institute of Physics.
Ogawa, S., Kimura, Y., Niwano, M., & Ishii, H. (2007). Trap elimination and injection switching at organic field effect transistor by inserting an alkane (C44H90) layer. Applied Physics Letters, 90(3). https://doi.org/10.1063/1.2431713