Quantitative esr analysis of deep defects in LEC-grown GaP

Defects in LEC GaP have been analyzed quantitatively using an ESR method. Transition-metal impurities and native defects were studied in as-grown crystals. The antisite defect, P_Ga, and the isolated gallium vacancy, V_Ga, were emphasized since no other method has given definite, quantitative information on these defects. P_Ga antisites are present in some Cr-doped and some Zn-dopeii samples in concentrations high enough to affect their electrical properties. V_Ga was not detected in as-grown crystals indicating that V_Ga concentrations are smaller than the antisite concentrations at least in p-type material. Typical ESR detection., limits for transition-metal impurities are in the middle 10¹⁴ cm⁻³ range. The method is especially sensitive to Fe traces which were observed in all the samples studied. Work performed while the author was a visiting scientist at TAF Freiburg,