Ultrahigh deep-UV sensitivity in graphene-gated β-Ga 2 O 3 phototransistors

Suhyun Kim, Sooyeoun Oh, Ji Hyun Kim

Research output: Contribution to journalArticlepeer-review

62 Citations (Scopus)


Deep-ultraviolet (UV) photodetectors based on ultrawide bandgap β-Ga 2 O 3 have a great potential in civil or military applications especially due to its inherent solar-blindness. Metal-semiconductor phototransistors based on exfoliated β-Ga 2 O 3 were fabricated using graphene as a highly transparent gate electrode. Controlling the potential barrier at the metal-semiconductor junction through the UV-transparent graphene gate expanded the difference between the UV-illuminated current and the dark current. Therefore, the photo-to-dark current ratio (PDCR) was raised by 6 orders of magnitude under the optimal gate bias. The performances of β-Ga 2 O 3 phototransistors were exceptionally superior among the deep-UV photodetectors based on wide bandgap semiconductor materials; PDCR of 6.0 × 10 8 and rejection ratio of 5.3 × 10 6 could be achieved. The synergetic combination of an ultrawide bandgap semiconductor and two-dimensional UV-transparent graphene provides a new opportunity for high performance deep-UV photodetectors.

Original languageEnglish
JournalACS Photonics
Publication statusPublished - 2019 Jan 1


  • deep-ultraviolet
  • gallium oxide
  • graphene
  • phototransistor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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