Pentacene thin film transistors with (polytetrafluoroethylene) PTFE-like encapsulation layer

(Polytetrafluoroethylene) PTFE-like films, deposited by using CHF3/Ar gas mixtures in a plasma reactor, have been used as encapsulation layers in pentacene thin film transistors. The PTFE-like encapsulation layers allow to carry out photolithographic processes without damaging pentacene film. However, the PTFE-like encapsulation layers are not effective in reducing hysteresis of electrical characteristics when measured in air. On the contrary, the degradation of the device electrical characteristics, induced by oxygen diffusion into pentacene film after storing the devices in air, is almost completely suppressed by the encapsulation with the PTFE-like films.

Graphical abstractPTFE-like films, deposited by using different CHF3/Ar gas mixtures in a plasma reactor, have been used as encapsulating layer for pentacene-OTFTs. They allow pentacene channel photolithographic definition and annealing of the passivated OTFTs (Fig. a).Furthermore, the encapsulation with PTFE-like films almost completely suppresses the degradation of the OTFT electrical characteristics (Fig. b), induced by oxygen diffusion into the pentacene film.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Plasma deposited PTFE films were used as encapsulation layer of pentacene OTFTs. ► PTFE-like films allow photolithographic definition of pentacene OTFTs. ► Electrical characteristics of encapsulated OTFTs were improved by thermal annealing. ► PTFE encapsulation suppresses OTFT degradation induced by oxygen diffusion.