Direct evidence for efficient energy transfer from N-related defects toPGaantisite complexes in GaP from optically detected magnetic resonance

The first direct evidence for highly efficient energy migration from N-related "shallow" defects to "deep" antisite-related complexes in GaP is presented. The efficiency of excitation-transfer processes is studied via the dye-laser-excited excitation spectra of the resonance signals observed in optically detected magnetic resonance (ODMR). On the basis of such ODMR excitation spectra, it is proved directly that the green GaP photoluminescence, due to bound-exciton recombination at N-related isoelectronic centers, is reduced by energy-transfer processes to ${\mathrm{P}}_{\mathrm{Ga}}$-related antisite centers. The mechanism responsible for this efficient energy transfer is discussed in terms of phonon-assisted tunneling.