57 Fe Mössbauer spectroscopy studies, following implantation of radioactive 57 Mn∗, have been conducted on InP and n-and p-type InAs at temperatures above 300 K. The 57 Mn∗ ions are produced at the ISOLDE facility at CERN, ionized and accelerated to 60 keV energy and implanted with fluences of⩽ 2× 10 12 ion/cm 2 into single crystal samples. Mössbauer spectra were collected with a parallel plate avalanche counter. Analysis of the Mössbauer spectra required three components: an asymmetric doublet attributed to Fe atoms in implantation induced damaged environments, a single line assigned to Fe on substitutional In sites and a weak symmetric doublet assigned to impurity–vacancy complexes. In InP the substitutional Fe component (Fe S) becomes significant above 400 K; while in InAs the Fe S fraction is already appreciable (> 30%) after implantation at room temperature. The asymmetric …