Enhancement of ultraviolet light responsivity of a pentacene phototransistor by introducing photoactive molecules into a gate dielectric

Toan Thanh Dao, Toshinori Matsushima, Motonobu Murakami, Kei Ohkubo, Shunichi Fukuzumi, Hideyuki Murata

Research output: Contribution to journalArticle

8 Citations (Scopus)


We demonstrated a new approach to fabricate an ultraviolet (UV) photodetector with a pentacene transistor structure where photoactive molecules of 6-[4′-(N,N-diphenylamino)phenyl]-3-ethoxycarbonylcoumarin (DPA-CM) were introduced into a poly(methyl methacrylate) (PMMA) gate dielectric. DPA-CM molecules strongly absorb UV light and form stable charge-separation states. When a negative gate voltage was scanned to a gate electrode of the transistor, the charge-separation states of DPA-CM molecules were converted into free electrons and holes. The free electrons traversed and subsequently reached an interface of the PMMA:DPA-CM layer and a polystyrene buffer layer, inducing accumulation of additional holes in a pentacene channel. Therefore, under 2.54mW/cm2 of 365nm UV irradiation, a marked increase in drain current by 6.1 × 102 times were obtained from the transistor. Moreover, the phototransistor exhibited a high light responsivity of 0.12 A/W which is about one order of magnitude larger than that of a conventional pentacene phototransistor [Lucas et al., Thin Solid Films 517, 280 (2009)]. This result will be useful for manufacturing of a high-performance UV photodetector.

Original languageEnglish
Article number02BB03
JournalJapanese journal of applied physics
Issue number2 PART 2
Publication statusPublished - Feb 27 2014
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

Cite this