We conduct comparative research on the density of states of electron- and hole- carrier trap levels (DTR(E)), dispersing inside the energy gap of a rubrene single crystal in a field effect transistor (FET) struction with Ca and Au hetero-electrodes for an ambipolar carrier injection mode, by using polymeric protection-layer materials on a Si substrate. Three different types of polymeric materials, poly(methyl-methacrylate) (PMMA), poly(styrene) (PS) and poly(chloro-styrene) (PCS) are employed. From the temperature (T)-dependent source-drain current and gate voltage (ISD-VG) transfer characteristics, the values of DTR(E) are evaluated. PS exhibits the most efficiently-balanced ambipolar carrier transport, which is superior to PMMA that is most typically used as the standard protection layer on a SiO2/doped-Si substrate. Discussions are made in the framework of a carrier multiple trap and release (CMTR) model.
@article{arxiv.2308.06903,
title = {Superior surface modification layer of poly(styrene) on SiO$_2$ gate insulator in rubrene single crystal field-effect transistor},
author = {Hua-Xue Zhou and Chong-Li Yang and Shi-Lin Li and Shota Kobayashi and Qifeng Yao and Katsumi Tanigaki and Hidekazu Shimotani},
journal= {arXiv preprint arXiv:2308.06903},
year = {2023}
}