Performance of Pentacene Based Organic Thin Film Transistor with an Octadecyltrichlorosilane Self-Assembled Monolayer Interface

The performance of a pentacene organic thin film transistor (OTFT) is discussed here where the substrate consists of a self-assembled monolayer (SAM) formed from octadecyltrichlorosilane (OTS) on the gate insulator. By changing the substrate from hydrophilic to hydrophobic interface defects are minimized. OTS SAM was studied for two samples according to OTS density 0.5 wt % and 1.0 wt % based on chloroform solution. The water contact angle was measured to investigate OTS growth and distribution. AFM and SEM were used to give organic thin film topography and morphology. The OTFT with 0.5 wt % OTS has a higher mobility and on/off ratio than the OTFT with 1.0 wt % OTS but has an increased threshold voltage. At the same time, the hysteresis at room temperature almost disappeared due to the OTS SAM processing.