Optically detected electron nuclear double resonance of anion antisite defects in GaP

Anion antisite defects in semi-insulating GaP single crystals (doped with group V atoms) are investigated with optically detected electron paramagnetic resonance and electron nuclear double resonance (ODEPR and ODENDOR) ODEPR and ODENDOR are measured as microwave- and microwave- and rf-induced changes of the magnetic circular dichroism of the optical absorption (MCDA), respectively. In GaP: V two P antisite defects are found in about equal concentration which within ENDOR precision have tetrahedral site symmetry with respect to the nearest P ligands. The two P_GaP₄ defects have only slightly differentg-factors and³¹P superhyperfine interactions, but differ by one order of magnitude in their spin-lattice relaxation times. Their optical properties are also different from those of the P_GaP₄ defects reported earlier in GaP: Cr. It is concluded that there is no experimental prove yet. that any of the P_GaP₄ defects hitherto observed in GaP in an isolated P_GaP₄ defect which is not associated with another defect to form an antisite related defect complex.