Rapid improvements in charge carrier mobility at ionic liquid/pentacene single crystal interfaces by self-cleaning

• Published in: Physical chemistry chemical physics : PCCP Vol. 22; no. 11; pp. 6131 - 6135
• Main Authors: Morino, Yusuke, Yokota, Yasuyuki, Hara, Hisaya, Bando, Ken-ichi, Ono, Sakurako, Imanishi, Akihito, Okada, Yugo, Matsui, Hiroyuki, Uemura, Takafumi, Takeya, Jun, Fukui, Ken-ichi
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 18.03.2020
• Subjects: Air gaps; Atomic force microscopy; Carrier mobility; Cleaning; Crystal defects; Current carriers; Electric double layer; Field effect transistors; Flat surfaces; Ionic liquids; Ions; Oxidation; Semiconductor devices; Single crystals; Transistors
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d0cp00149j

We report the rapid improvement in the carrier mobility of the electric double layer field-effect transistor based on the ionic liquid (IL)/pentacene single crystal interface. Generally, the surface oxidation of the pentacene single crystal is unavoidable, and the considerable degradation restricts the performance of the field-effect transistor. However, the formation of the IL/pentacene single crystal interface resolves this problem by increasing the carrier mobility by approximately twice the initial value within a few hours. Furthermore, frequency-modulation atomic force microscopy revealed that the aforementioned rapid improvement is attributed to the appearance of a clean and flat surface of the pentacene single crystal via the defect-induced spontaneous dissolution of pentacene molecules into the IL. The field-effect mobility increases with time for a few hours because of the spontaneous dissolution of the defect sites.