Concentration-dependent mobility in organic field-effect transistors probed by infrared spectromicroscopy of the charge density profile

Meyertholen, A. D.; Li, Z. Q.; Basov, D. N.; Fogler, M. M.; Martin, M. C.; Wang, G. M.; Dhoot, A. S.; Moses, D.; Heeger, A. J.

Concentration-dependent mobility in organic field-effect transistors probed by infrared spectromicroscopy of the charge density profile

Authors

Description

We show that infrared imaging of the charge density profile in organic field-effect transistors (FETs) can probe transport characteristics which are difficult to access by conventional contact-based measurements. Specifically, we carry out experiments and modeling of infrared spectromicroscopy of poly(3-hexylthiophene) (P3HT) FETs in which charge injection is affected by a relatively low resistance of the gate insulators. We conclude that the mobility of P3HT has a power-law density dependence, which is consistent with the activated transport in disorder-induced tails of the density of states.
3+ pages, 2 figures