Electrical characterization of AlxGa1-xN for UV photodetector applications

A. Saxler*, M. Ahoujja, W. C. Mitchel, P. Kung, D. Walker, M. Razeghi

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

2 Scopus citations


Ultraviolet photodetectors have many military and commercial applications. However, for many of these applications, the photodetectors must be solar blind. This means that the photodetectors must have a cutoff wavelength of less than about 270 nm. Semiconductor based devices would then need energy gaps of over 4.6 eV. In the AlxGa1-xN system, the aluminum mole fraction, x, required is over 40%. As the energy gap is increased, doping becomes much more difficult, especially p-type doping. This report is a study of the electrical properties of AlxGa1-xN to enable better control of the doping. Magnesium doped p-type AlxGa1-xN has been studied using high-temperature Hall effect measurements. The acceptor ionization energy has been found to increase substantially with the aluminum content. Short-period superlattices consisting of alternating layers of GaN:Mg and AlGaN:Mg were also grown by low-pressure organometallic vapor phase epitaxy. The electrical properties of these superlattices were measured as a function of temperature and compared to conventional AlGaN:Mg layers. It is shown that the optical absorption edge can be shifted to shorter wavelengths while lowering the acceptor ionization energy by using short-period superlattice structures instead of bulk-like AlGaN:Mg. Silicon doped n-type films have also been studied.

Original languageEnglish (US)
Pages (from-to)211-222
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 1999
EventProceedings of the 1999 Photodetectors: Materials and Devices IV - San Jose, CA, USA
Duration: Jan 27 1999Jan 29 1999

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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