Dynamics of low temperature excitons in Fe-doped GaN

The recombination processes of excitons in Fe-doped GaN have been characterized by time-resolved photoluminescence measurement. The photoluminescence shape at different excitation powers revealed that the hole capture process by Fe²⁺ centers has always existed in doped GaN. Decreasing of the fast component in the biexponential decay curves with increasing iron concentration indicates the enhancive contribution of the hole capture process. Furthermore, the structures of an iron-related acceptor and complex bound exciton were confirmed by the dependence of lifetime constants on the localization energy. Also, the extended wave function of the hole from the complex bound exciton will enable spin coupling between isolated iron ions. (paper)