Effect of 5 MeV proton irradiation damage on performance of β-Ga2O3 photodetectors

Shihyun Ahn, Yi Hsuan Lin, Fan Ren, Sooyeoun Oh, Younghun Jung, Gwangseok Yang, Jihyun Kim, Michael A. Mastro, Jennifer K. Hite, Charles R. Eddy, Stephen J. Pearton

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67 Citations (Scopus)


Planar thin film β-Ga2O3 photodetectors were irradiated with 5 MeV protons at doses from 1013 to 1015cm-2, and the resulting effects on photocurrent, responsivity, quantum efficiency, and photo-to-dark current ratio at 254 nm wavelength were measured at both 25 and 150 °C. The photocurrent increased with dose due to the introduction of damage from nonionizing energy loss by the protons. The total calculated vacancy concentration increased from 5 × 1015 to 5 × 1017 cm-3 over the dose range investigated. The dark current increased in proportion with the implant dose, leading to a decrease in the ratio of photocurrent to dark current. The photocurrent induced by 254 nm illumination increased with dose, from ∼0.3 × 10-7 A at 25 °C for a dose of 1013cm-2 to ∼10-6 A at a dose of 1015cm-2 at a fixed light intensity of 760 μW/cm2. The photo-to-dark current ratio decreased from ∼60 in the control samples to ∼9 after proton doses of 1015cm-2, with corresponding external quantum efficiencies of ∼103% in control samples, ∼2 × 103% for a dose of 1013cm-2, and 104% for a dose of 1015cm-2. The mechanism for the increase in photocurrent is the introduction of gap states, since the dark current of the photodetectors was increased by illuminating with sub-bandgap (red or green laser light) for the proton irradiated samples.

Original languageEnglish
Article number041213
JournalJournal of Vacuum Science and Technology B: Nanotechnology and Microelectronics
Issue number4
Publication statusPublished - 2016 Jul 1

Bibliographical note

Publisher Copyright:
© 2016 American Vacuum Society.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Materials Chemistry


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