Improvement of transparent organic thin film transistor performance by inserting a lithium fluoride buffer layer

Pentacene-based highly transparent thin-film transistors which are fabricated by inserting a thin insulating lithium fluoride layer between pentacene and transparent source/drain electrodes are presented. Through this method, device performance can be enhanced dramatically with an average transmittance of as high as 69.72% in the visible region, indicating that the LiF layer is not responsible for optical transmission. For example, there is a significant improvement of a few times with the introduction of the 1-nm -thick LiF layer, the maximum saturation drain current and the field-effect mobility. These improvements are attributed to the energy band realignment and the tunneling process.