An Experimental Study of the Effects of Source/Drain to Gate Overlap in Pentacene Thin-Film Transistors

The effects of the source/drain (S/D) to gate overlap on the electrical characteristics of pentacene organic thin-film transistors (OTFTs) are reported. The S/D to gate overlap dimension was varied by adjusting the gate width, while the channel length and width were fixed. The threshold voltage was found to decrease on increasing the overlap dimension; in contrast, the field-effect mobility increased. These characteristic variations are explained on aspects of charge injection and transport properties in pentacene OTFTs, due to the presence of S/D to gate overlaps. The results demonstrate the significant effect of the overlap on the OTFT performance. (C) 2012 The Japan Society of Applied Physics