Solar-blind AlxGa1-xN p-i-n photodetectors grown on LEO and non-LEO GaN

Peter Sandvik*, Danielle Walker, Patrick Kung, Kan Mi, Fatemeh Shahedipour, Vipan Kumar, Xinghong Zhang, Jacqueline Diaz, Christopher Jelen, Manijeh Razeghi

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

14 Scopus citations


There is currently a strong interest in developing solid-state, ultraviolet (UV) photodetectors for a variety of applications. Some of these are early missile threat warning, covert space to space communications, flame monitoring, UV radiation monitoring and chemical/biological reagent detection. The III-Nitride material system is an excellent candidate for such applications due to its wide, direct bandgaps and robust material nature. However, despite many inherent material advantages, the III-Nitride material system typically suffers from a large number of extended defects which degrade material quality and device performance. One technique aimed at reducing defect densities in these materials is lateral epitaxial overgrowth (LEO). In this work, we present a preliminary comparison between AlGaN UV, solar-blind p-i-n photodiodes fabricated from LEO GaN and non-LEO GaN. Improvements in both responsivity and rejection ratio are observed, however, further device improvements are necessary. For these, we focus on the optimization of the p-i-n structure and a reduction in contact resistivity to p-GaN and p-AlGaN layers. By improving the structure of the device, GaN p-i-n photodiodes were fabricated and demonstrate 86% internal quantum efficiency at 362 nm and a peak to visible rejection ratio of 105. Contact treatments have reduced the contact resistivity to p-GaN and p-AlGaN by over one order of magnitude from our previous results.

Original languageEnglish (US)
Pages (from-to)265-272
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2000
EventPhotodetectors: Materials and Devices V - San Jose, CA, USA
Duration: Jan 25 2000Jan 28 2000

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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