Internal photoemission spectroscopy measurement of Alq3/cathode interface by three layered electron only device

Eiji Itoh, Shinya Takaishi, Keiichi Miyairi

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


We have investigated the Schottky barrier height for electrons at aluminum tris (8-hydroxyquinoline) (Alq3)/cathode interfaces by internal photoemission (IPE) measurement. A three layered device consisting of ITO/TiO2/intermediate layer (IL)/Alq3/cathode structure was used to fabricate the "electron-only device" and to reduce the equivalent thickness of TiO2 and IL stack. The measured barrier heights were 0.86, 1.05, 1.3 and 1.55 eV for MgAg, Al, Ag and Au electrodes, and it gradually decreased with external voltage and it was explained as Schottky effect. Barrier height showed linear relationship with work-function and electronegativity of cathode materials. The slope parameter of 0.6 with electronegativity was attributed to the interfacial charge transfer through the metal-induced gap states at the cathode/Alq3 interface.

Original languageEnglish
Pages (from-to)791-794
Number of pages4
JournalThin Solid Films
Issue number2
Publication statusPublished - 2009 Nov 30
Externally publishedYes


  • Alq
  • Barrier height
  • Electron only device
  • Internal photoemission

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry


Dive into the research topics of 'Internal photoemission spectroscopy measurement of Alq<sub>3</sub>/cathode interface by three layered electron only device'. Together they form a unique fingerprint.

Cite this