An organic thin film transistor (OTFT) comprising a gate electrode, a gate insulating
film, an organic active layer and a source/drain electrode, or a gate electrode,
a gate insulating film, a source/drain electrode and an organic active layer, sequentially
formed on a substrate, wherein the gate insulating film is a multi-layered insulator
comprising a first layer of a high dielectric material and a second layer of an
insulating organic polymer compatible with the organic active layer, the second
layer being positioned directly under the organic active layer. The OTFT of the
present invention shows low threshold and driving voltages, high charge mobility,
and high Ion/Ioff, and it can be prepared by a wet process.