Time-resolved photoluminescence has been employed to study the donor-accept
or pair recombination kinetics of the yellow (similar to 2.3 eV) and blue (
similar to 2.8 eV) luminescence bands in Si- and Mg-doped GaN layers, respe
ctively. As the Si doping concentration in Si-doped GaN increases, the life
time tau(1/e) of the yellow luminescence decreases, indicating that a shall
ow Si donor is the origin of the yellow luminescence. The blue luminescence
is most likely due to a shallow Mg acceptor and a deep donor composed of a
Mg acceptor-nitrogen vacancy complex, as seen by the independence of tau(1
/e) on the Mg concentration measured by secondary ion mass spectroscopy in
the range (2.5-6.0)x10(19) cm(-3). As the temperature is increased from 10
to 300 K, the lifetimes for the yellow and blue luminescence remain nearly
constant, indicating that the distribution of electrons and holes bound to
donors and acceptors does not change much with increasing temperature. (C)
2000 American Institute of Physics. [S0003-6951(00)03407-0].