Electrical Properties of Heat-Treated C60 Field Effect Transistor Prepared on Polyimide Gate Insulator

Abstract

Fullurence (C60)-based n-channel field effect transistors (FETs) have been fabricated on polyimide gate insulators as an alternative to conventional oxide gate insulators. The field effect mobility µe of C60 FET was improved to higher than 0.1 cm2 V-1 s-1 by heat treatment at 160 °C. This improvement was attributed to the de-doping of oxygen molecules, which were adsorbed by short-term exposure to air during sample transfer. The C60 films deposited on polyimide become amorphous even after the heat treatment or heating the sample during deposition. On the other hand, the crystalline phase of C60 appears when the films were deposited on pentacene-coated polyimide. Both the field effect mobility and the conductance of bulk C60 were increased markedly by the insertion of an ultrathin pentance layer between C60 and the polyimide gate insulator.