Irradiation-induced defect configurations in Ge substrates characterised with perturbed angular correlation

Perturbed angular correlation (PAC) studies with radioactive In-111 probes in crystalline Ge substrates have previously established the presence of two distinct defective configurations following either electron or ion irradiation. Though such defects have been tentatively identified as In-vacancy (In-V) and In-interstitial (In-I) configurations, an unambiguous assignment is still lacking and conflicting interpretations are apparent. For the present report, a series of experiments have been performed as functions of ion dose, background dopant and dopant concentration to examine both the validity of previous suppositions and produce supplementary evidence to aid in determining the microscopic nature of the two defective configurations. The relative fractions of the defective configurations were generally insensitive to dopant concentration and thus did not exhibit a significant Fermi level dependence. The present results suggest that the formation of an In-V complex is not the result of elastic interaction between an In-acceptor and neutral vacancy. Alternative interpretations are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.