Effect of gate metal on polymer transistor with glass substrate

Abstract

Poly(3-hexylthiophene) (P3HT) field-effect transistors (FETs) are fabricated on glass substrates with Si O 2 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 cm 2 ∕ V s for ITO and Al gates to 10 − 2 cm 2 ∕ V s for Cr gate. After O 2 plasma treatment, the Si O 2 roughness can be made as low as 0.7 nm . The mobility is further improved up to 0.3 cm 2 ∕ 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 O 2 surface over Cr gate.