Electrically detected magnetic resonance investigations of gallium phosphide green light-emitting diodes

Transport processes and degradation of GaP:N green light-emitting diodes have been investigated using electrically detected magnetic resonance (EDMR). An isotropic EDMR signal with a g value of g=1.996 and a linewidth of ΔH_po=68 G can be observed at low temperatures after current degradation. The signal exhibits a T^-2 temparature dependence indicating a spin relaxation process faster than the relevant transport step. The microscopic origin of the EDMR signal - most probably recombination at a n-type dopant-related defect near the p-n interface - is analyzed with respect to possible degradation mechanisms.