High detectivity visible-blind SiF4 grown epitaxial graphene/SiC Schottky contact bipolar phototransistor

Venkata S.N. Chava, Bobby G. Barker, Anusha Balachandran, Asif Khan, G. Simin, Andrew B. Greytak, M. V.S. Chandrashekhar

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


We report the performance of a bipolar epitaxial graphene (EG)/p-SiC/n+-SiC UV phototransistor fabricated with a Schottky (EG)/SiC junction grown using a SiF4 precursor. The phototransistor showed responsivity as high as 25 A/W at 250 nm in the Schottky emitter (SE) mode. The Schottky collector (SC) mode showed a responsivity of 17 A/W at 270 nm with a visible rejection (270 nm:400 nm)>103. The fastest response was seen in the SC-mode, with 10 ms turn-on and 47 ms turn-off, with a noise equivalent power of 2.3 fW at 20 Hz and a specific detectivity of 4.4 × 1013 Jones. The high responsivity is due to internal gain from bipolar action. We observe additional avalanche gain from the device periphery in the SC-mode by scanning photocurrent microscopy but not in the SE-mode. This high-performance visible-blind photodetector is attractive for advanced applications such as flame detection.

Original languageEnglish (US)
Article number243504
JournalApplied Physics Letters
Issue number24
StatePublished - Dec 11 2017
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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