We report on experiments in which picosecond ultrasonic techniques are used to investigate the modification of interfacial bonding that results from ion implantation. The bonding is studied through measurements of the acoustic reflection coefficient at the interface. This method is nondestructive and can be used to create a map of the variation of the bonding over the area of the interface.

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Preparation and structure of 1-8 monolayer thick epitaxial iron oxide films grown on Pt (111) Lowenergy electron diffraction intensity analysis of the atomic geometry of p(1×1) monolayers of bismuth on GaAs(110)The preferred bonding site of Sb on Si͑100͒ is investigated using transmission ion channeling. A Monte Carlo simulation that includes a model for channeled ion energy loss has been used to calculate scattering yields and energy distributions for trial adatom sites. A method of data collection and analysis was developed to use the calculated scattering yields and energy distributions for quantitative site determination. The Sb site thus found agrees well with previous experiments on this system, namely, the Sb is in a modified bridge site with a bond length of 2.80Ϯ0.10 Å and a distance above the bulk-extrapolated silicon surface of 1.63Ϯ0.10 Å. However, the vibrational amplitude necessary for the simulated energy distributions to match experiment is anisotropic, apparently in contradiction with other results. A possible resolution is proposed.

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