Affiliations: Micro and Nanosciences Laboratory, Helsinki University
of Technology, Helsinki, Finland | Research Institute for Networks and Communications
Engineering, Dublin City University, Dublin 9, Ireland | HASYLAB am DESY, Hamburg, Germany | Mineralogisch-Petrographisches Institut,
Universität Hamburg, Hamburg, Germany
Note: [] Corresponding author. A. Lankinen, Micro and Nanosciences
Laboratory, Helsinki University of Technology, P.O. Box 3500, FIN-02015 TKK,
Finland. E-mail: aapo.lankinen@tkk.fi
Abstract: X-ray excited optical luminescence (XEOL) measurements of Mg-doped
GaN were made using continuous spectrum of synchrotron radiation. The samples
were grown by metalorganic vapour phase epitaxy (MOVPE) on
α-Al_{2}O_{3} substrates. The
electrical activation of the Mg dopants by thermal annealing was detected in
the room-temperature XEOL spectra, but not in the ultraviolet light excitation
low-temperature photoluminescence (PL) spectra. The better results of the X-ray
excitation over the ultraviolet excitation PL is attributed to the larger
penetration depth of X-rays in heavily Mg-doped GaN. The activation of the Mg
dopants was confirmed using Hall measurements.
