Electrical and optical properties of Ga2O3/ CuGaSe2 heterojunction photoconductors

Kenji Kikuchi, Shigeyuki Imura, Kazunori Miyakawa, Misao Kubota, Eiji Ohta

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


In this study, the feasibility of using a photoconductor with a Ga 2O3/CuGaSe2 heterojunction for visible light sensors was investigated. We propose a hole-blocking structure using gallium oxide (Ga2O3) for CuIn1 - xGa xSe1 - ySy (CIGS) thin film to reduce dark current. Experimental results showed that this structure drastically reduced the dark current. Then, avalanche multiplication phenomenon was observed at an applied voltage of over 6 V. However, this structure had sensitivity only in the ultraviolet light region. It seemed the depletion region in the heterojunction spread almost completely in the Ga2O3 layer but not in the CIGS layer because the carrier density of the non-doped Ga2O 3 layer was much lower than that of the CIGS layer. We therefore used tin-doped Ga2O3 (Ga2O3:Sn) for the n-type layer to increase carrier density. As a result, the depletion region shifted to the CIGS film and the cells had sensitivity in all visible regions. These results indicate that the Ga2O3:Sn/CuGaSe 2 heterojunction is feasible for visible light photoconductors.

Original languageEnglish
Pages (from-to)635-637
Number of pages3
JournalThin Solid Films
Publication statusPublished - 2014 Jan 1


  • Cadmium free buffer
  • Copper indium gallium selenide
  • Gallium oxide

ASJC Scopus subject areas

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


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