GaN p-i-n photodiodes with high visible-to-ultraviolet rejection ratio

Patrick Kung*, Xiaolong Zhang, Danielle Walker, Adam Saxler, Manijeh Razeghi

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

8 Scopus citations


Ultraviolet photodetectors are critical components in many applications, including ultraviolet astronomy, flame sensors, early missile threat warning and space-to-space communications. Because of the presence of strong infrared radiation in these situations, the photodetectors have to be solar blind, i.e. able to detect ultraviolet radiation while not being sensitive to infrared. AlxGa1-xN is a promising material system for such devices. AlxGa1-xN materials are wide bandgap semiconductors, with a direct bandgap whose corresponding wavelength can be continuously tuned from 200 to 365 nm. AlxGa1-xN materials are thus insensitive to visible and infrared radiation whose wavelengths are higher than 365 nm. We have already reported the fabrication and characterization of AlxGa1-xN-based photoconductors with a cut-off wavelength tunable from 200 to 365 nm by adjusting the ternary alloy composition. Here, we present the growth and characterization of GaN p-i-n photodiodes which exhibit a visible-to-ultraviolet rejection ratio of 6 orders of magnitude. The thin films were grown by low pressure metalorganic chemical vapor deposition. Square mesa structures were fabricated using dry etching, followed by contact metallization. The spectral response, rejection ratio and transient response of these photodiodes is reported.

Original languageEnglish (US)
Pages (from-to)214-220
Number of pages7
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 1998
EventPhotodetectors: Materials and Devices III - San Jose, CA, United States
Duration: Jan 28 1998Jan 30 1998


  • GaN
  • Photodetector
  • Photodiode
  • Rejection ratio
  • Responsivity
  • Ultraviolet
  • p-i-n

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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