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Proceedings Paper

Electrical characterization of AlxGa1-xN for UV photodetector applications
Author(s): Adam W. Saxler; Mohamad Ahoujja; W. C. Mitchel; Patrick Kung; Danielle Walker; Manijeh Razeghi
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Paper Abstract

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.

Paper Details

Date Published: 7 April 1999
PDF: 12 pages
Proc. SPIE 3629, Photodetectors: Materials and Devices IV, (7 April 1999); doi: 10.1117/12.344558
Show Author Affiliations
Adam W. Saxler, Air Force Research Lab. (United States)
Mohamad Ahoujja, Air Force Research Lab. (United States)
W. C. Mitchel, Air Force Research Lab. (United States)
Patrick Kung, Northwestern Univ. (United States)
Danielle Walker, Northwestern Univ. (United States)
Manijeh Razeghi, Northwestern Univ. (United States)

Published in SPIE Proceedings Vol. 3629:
Photodetectors: Materials and Devices IV
Gail J. Brown; Manijeh Razeghi, Editor(s)

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