Abstract
Poly(3-hexylthiophene) (P3HT) field-effect transistors (FETs) are fabricated on glass substrates with Si O2 as a gate dielectric over the gate. Indium tin oxide (ITO), Al, and Cr are employed as gate metals. For spin-coated FET, the mobility increases from 10-4 - 10-5 cm2 V s for ITO and Al gates to 10-2 cm2 V s for Cr gate. After O2 plasma treatment, the Si O2 roughness can be made as low as 0.7 nm. The mobility is further improved up to 0.3 cm2 V s by dip-coating P3HT. ""Crossed rods"" such as morphology can be observed in dip-coated FET with high mobility, indicating high degree of self-assembly facilitated by the flat Si O2 surface over Cr gate. © 2006 American Institute of Physics.