High crystalline dithienosilole-cored small molecule semiconductor for ambipolar transistor and nonvolatile memory

Woonggi Kang, Minwoo Jung, Wonsuk Cha, Sukjae Jang, Youngwoon Yoon, Hyunjung Kim, Hae Jung Son, Doh Kwon Lee, Bongsoo Kim, Jeong Ho Cho

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Abstract

We characterized the electrical properties of a field-effect transistor (FET) and a nonvolatile memory device based on a solution-processable low bandgap small molecule, Si1TDPP-EE-C6. The small molecule consisted of electron-rich thiophene-dithienosilole-thiophene (Si1T) units and electron-deficient diketopyrrolopyrrole (DPP) units. The as-spun Si1TDPP-EE-C6 FET device exhibited ambipolar transport properties with a hole mobility of 7.3 × 10-5 cm2/(V s) and an electron mobility of 1.6 × 10-5 cm2/(V s). Thermal annealing at 110 °C led to a significant increase in carrier mobility, with hole and electron mobilities of 3.7 × 10-3 and 5.1 × 10-4 cm2/(Vs), respectively. This improvement is strongly correlated with the increased film crystallinity and reduced π-π intermolecular stacking distance upon thermal annealing, revealed by grazing incidence X-ray diffraction (GIXD) and atomic force microscopy (AFM) measurements. In addition, nonvolatile memory devices based on Si1TDPP-EE-C6 were successfully fabricated by incorporating Au nanoparticles (AuNPs) as charge trapping sites at the interface between the silicon oxide (SiO2) and cross-linked poly(4-vinylphenol) (cPVP) dielectrics. The device exhibited reliable nonvolatile memory characteristics, including a wide memory window of 98 V, a high on/off-current ratio of 1 × 103, and good electrical reliability. Overall, we demonstrate that donor-Acceptor-type small molecules are a potentially important class of materials for ambipolar FETs and nonvolatile memory applications.

Original languageEnglish
Pages (from-to)6589-6597
Number of pages9
JournalACS Applied Materials and Interfaces
Volume6
Issue number9
DOIs
Publication statusPublished - 2014 May 14

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)

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