Fabrication and characterization of poly(3-hexylthiophene)-based field-effect transistors with silsesquioxane gate insulators

The preparation of organic-inorganic hybrid gate dielectrics of poly(methyl silsesquioxane) (PMSQ) at a low processing temperature has been studied for use in organic field-effect transistors (OFETs) by the solution process. It is found that the electrical resistivity of a PMSQ film synthesized by a sol-gel method is significantly influenced by the synthesis conditions such as the type of organic solvent used and water content. PMSQ films prepared in toluene show a high resistivity of over 10(14) Omega cm even at a low thermal treatment of 150 degrees C, which is attributed to the decrease in the silanol concentration of the PMSQ films. Top-contact OFET fabricated on a PMSQ-coated SiO(2) gate dielectric using poly(3-hexylthiophene) exhibits mobility improvement similarly to devices with self-assembled monolayer-modified SiO(2) dielectrics.