Comparison of the atomic structure of InP amorphized by electronic or nuclear ion energy-loss processes

InP was amorphized by ion irradiation in two very different regimes: (i) 185 MeV Au irradiation, where the energy loss was predominantly via inelastic processes (electronic stopping), or (ii) Se irradiation in an energy range of 0.08-7 MeV, where elastic processes (nuclear stopping) were dominant. The structural parameters of the amorphous phase were determined for as-irradiated and thermally relaxed samples using extended x-ray absorption fine structure spectroscopy. Despite the fundamentally different energy transfer mechanisms, no significant difference in the atomic structure of the two amorphized samples was observed. We attribute this result to a common "melt and quench" process responsible for amorphization. In fact, the measured structural parameters for the amorphized samples, including the fraction of homopolar In-In bonding, were consistent with simulations of the amorphous phase produced by assuming a quench from the melt.