AlxGa1-xN p-i-n photodiodes on sapphire substrates

D. Walker, P. Kung, P. Sandvik, J. Wu, M. Hamilton, I. H. Lee, J. Diaz, M. Razeghi

Research output: Contribution to journalConference articlepeer-review

10 Citations (Scopus)


We report the fabrication and characterization of AlxGa1-xN p-i-n photodiodes (0.05≤x≤0.30) grown on sapphire by low-pressure metalorganic chemical vapor deposition. The devices present a visible-rejection of about four orders of magnitude with a cutoff wavelength that shifts from 350 nm to 291 nm. They also exhibit a constant responsivity for five decades (30 mW/m2 to 1 kW/m2) of optical power density. Using capacitance measurements, the values for the acceptor concentration in the p-AlxGa1-xN region and the unintentional donor concentration in the intrinsic region are found. Photocurrent decays are exponential for high load resistances, with a time constant that corresponds to the RC product of the system. For low load resistances the transient response becomes non-exponential, with a decay time longer than the RC constant.

Original languageEnglish
Pages (from-to)193-198
Number of pages6
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 1999
Externally publishedYes
EventProceedings of the 1999 Photodetectors: Materials and Devices IV - San Jose, CA, USA
Duration: 1999 Jan 271999 Jan 29

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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