The combinatorial optimization simulated annealing algorithm is applied to the analysis of Rutherford backscattering data. The analysis is fully automatic, i.e., it does not require time-consuming human intervention. The algorithm is tested on a complex iron-cobalt silicide spectrum, and all the relevant features are successfully determined. The total analysis time using a PC 486 processor running at 100 MHz is comparable to the data collection time, which opens the way for on-line automatic analysis.

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Ion Beam Analysis (IBA) includes a group of techniques for the determination of elemental concentration depth profiles of thin film materials. Often the final results rely on simulations, fits, and calculations, made by dedicated codes written for specific techniques. Here we evaluate numerical codes dedicated to the analysis of Rutherford Backscattering Spectrometry (RBS), non-Rutherford Elastic Backscattering Spectrometry, Elastic Recoil Detection Analysis, and non-resonant Nuclear Reaction Analysis data. Several software packages have been presented and made available to the community. New codes regularly appear, and old codes continue to be used and occasionally updated and expanded. However, those codes have to date not been validated, or even compared to each other. Consequently, IBA practitioners use codes whose validity, correctness and accuracy have never been validated beyond the authors' efforts. In this work, we present the results of an IBA software intercomparison exercise, where seven different packages participated. These were DEPTH, GISA, DataFurnace (NDF), RBX, RUMP, SIMNRA (all analytical codes) and MCERD (a Monte Carlo code). In a first step, a series of simulations were defined, testing different capabilities of the codes, for fixed conditions. In a second step, a set of real experimental data were analysed. The main conclusion is that the codes perform well within the limits of their design, and that the largest differences in the results obtained are due to differences in the 3 fundamental databases used (stopping power and scattering cross section). In particular, spectra can be calculated including Rutherford cross-sections with screening, energy resolution convolutions including energy straggling, and pileup effects, with agreement between the codes available at the 0.1% level. This same agreement is also available for the non-RBS techniques. This agreement is not limited to calculation of spectra from particular structures with predetermined parameters, but also extends to extracting information from real data. In particular, we have shown data from an Sb implanted sample where the Sb fluence was certified with an uncertainty of 0.6%. For this sample, and using SRIM03 stopping powers for 1.5 MeV 4He in Si, the codes were able to extract the Sb fluence with an average 0.18% deviation from the certified value and a 0.11% agreement between the codes. Thus IBA is a suitable technique for accurate analysis where traceability is critical. These results confirm that available IBA software packages are, within their design limitations, consistent and reliable. The protocol established may be readily applied to validate future IBA software as well.

We investigate interactions between Mott-Wannier (MW) and Frenkel excitons in a family of hybrid structures consisting of thin organic (polyfluorene) films placed in close proximity (systematically adjusted by GaN cap layer thickness) to single inorganic [(Ga,In)N∕GaN] quantum wells (QWs). Characterization of the QW structures using Rutherford backscattering spectrometry and atomic force microscopy allows direct measurement of the thickness and the morphology of the GaN cap layers. Time-resolved photoluminescence experiments in the 8–75 K temperature range confirm our earlier demonstration that nonradiative energy transfer can occur between inorganic and organic semiconductors. We assign the transfer mechanism to resonant Förster (dipole-dipole) coupling between MW exciton energy donors and Frenkel exciton energy acceptors and at 15 K we find transfer efficiencies of up to 43%. The dependence of the energy transfer rate on the distance R between the inorganic QW donor dipole and organic film acceptor dipole indicates that a plane-plane interaction, characterized by a 1∕R2 variation, best describes the situation found in our structures