Observation of the hysteresis behavior of pentacene thin-film transistors in I-V and C-V measurements

Current-voltage and capacitance-voltage measurements of the organic thin-film transistors (OTFTs) were performed to observe the change of the surface state of gate dielectrics using various surface treatments. The hexamethyldisilazane (HMDS)-treated OTFTs, which has few OH groups on the dielectric surface, showed little hysteresis behavior than that of other surface-treated OTFTs. In particular, when the positive gate bias (for a depletion state) was applied, more hysteresis was observed, indicating that OH groups on a gate dielectric are responsible for the electron trapping in the channel. However, when the surface is terminated with (CH3) 3 -Si, eliminating OH groups by HMDS treatment, much less hysteresis was observed in the positive direction. Therefore, it seems apparent that an OH -free surface is desirable for a more stable operation of OTFTs.