\u201cIon irradiation effects on the transport properties and degradation mechanism of organic field effect transistors\u201d

"Ion Irradiation Effects on The Transport Properties and Degradation Mechanisms of Organic Field-Effect Transistors" Motivation: The remarkable advances recently made in the development of organic semiconductor field effect devices (OFET) prospect challenging applications in the field of low-cost flexible, lightweight, and conformal electronics. One of the interesting features of organic active layers is their capability to respond to the environment chemical composition, but this unfortunately opens up the issue of long-term stability of devices based on organic materials, as oxidation is believed to be a major reason for early device failure.The focus of this proposal is to investigate the potentiality of low energy ion irradiation in the reduction and control of the degradation of the organic material due to the exposure to atmosphere (i.e. oxygen and water). The damage induced by the ions can induce a rearrangement of the molecular alignment by breaking covalent bonds, crosslinking the neighboring polymer chains and forming a hydrogen-depleted three dimensional carbon network.The strong molecular structure modification would affect carrier mobility and the threshold voltage of the device, but since the electrical transport in OFETs occurs in a few active molecular layers at the organic/dielectric interface, a controlled damage depth distribution should preserve the functionality of the organic active layer. We propose to study the variations of the transport parameters by characterizing the optical and electrical properties of the material by means of optical absorption, Fourier Transform Infrared (FTIR) spectroscopy and terahertz spectroscopy analyses, and by electrical transport analyses. These experiments will be carried out in collaboration with M. Nastasi\u2019s and A.J. Taylor\u2019s research groups at the Center for Nanoscale Integration (CINT) of the Los Alamos Laboratory (U.S.A.