EPR Observation of an Au‐Fe Complex in Silicon: I. Experimental Data

After quenching of Au‐doped FZ silicon an anisotropic axially symmetric EPR spectrum is observed. The spectrum exhibits a hyperfine interaction with 197 Au nuclei ( I = ½). In samples which were intentionally doped with isotopically enriched 57 Fe ( I = ½) an additional hyperfine interaction with this nucleus is observed. Due to the large nuclear electric quadrupole moment of 107 Au the nuclear quadrupole interaction strongly influences the EPR spectrum. From this effect a lower limit for the quadrupole interaction can be derived by a computer diagonalization of the spin Hamiltonian. From the observed hyperfine interactions and the known properties of Fe and Au in silicon it is concluded that this spectrum originates from a [Au s Fe i ] complex.