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

• Dao, Toan Thanh

• Matsushima, Toshinori

• Murakami, Motonobu

• Ohkubo, Kei

• Fukuzumi, Shunichi

• Murata, Hideyuki

Abstract

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 2.54 mW/cm^2 of 365 nm UV irradiation, a marked increase in drain current by 6.1 × 10^2 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 (2009) 280]. This result will be useful for manufacturing of a high-performance UV photodetector.

identifier:https://dspace.jaist.ac.jp/dspace/handle/10119/12912

Journal

• Japanese Journal of Applied Physics

  Japanese Journal of Applied Physics 53 (2s), 02BB03-1-02BB03-5, 2014-01-29

  IOP Publishing

Details

• CRID: 1050564288760316672
• NII Article ID: 120005652016
• ISSN: 00214922
• Web Site: http://hdl.handle.net/10119/12912
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles
  • KAKEN