Host: The Japan Society of Vacuum and Surface Science
In this study, we use electric-field induced sum-frequency generation (SFG) spectroscopy to probe the channel formation process of OFETs during operation. For a series of experiments, we prepared OFETs fabricated with 2,7-diphenyl[1]benzothieno[3,2-b][1]benzothiophene (DPh-BTBT) thin films. The gate dielectric layer was composed of a silicon dioxide and a hexamethyldisilazane (HMDS) monolayer. As a result, we succeeded in probing changes in the internal electric field due to charge accumulation while observing SFG peaks of CH stretching modes. Those molecular vibrational modes were derived from methyl groups of HMDS and phenyl groups of DPh-BTBT. We discuss the correlation between each molecular species and the charge accumulation.
