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A synthetic route for the preparation of luminescent PbS nanoparticles encapsulated in SiO2 at room temperature by the sol‐gel process is presented. The particle size and morphology of the PbS nanoparticles were observed by transmission electron microscopy (TEM). The particle sizes were estimated from the X‐ray diffraction (XRD) peaks using the Scherrer's equation. The measured particle sizes were in the range of 10 to 50 nm inside the SiO2 matrix. The cathodoluminescence (CL) measured with a Fiber Optics PC2000 spectrometer showed the emission peak to be at the wavelength of 680 nm. The phosphor was degraded in an oxygen atmosphere. The chemical composition of the prepared samples was analyzed by an energy dispersive spectrometer (EDS). X‐ray photoelectron spectrometer (XPS) was used to measure the surface chemical composition of the SiO2:PbS nanoparticles before and after electron degradation. XPS analysis on the degraded spot showed the development of characteristic SiO, SiOx and elemental Si peaks on the low‐energy side of the SiO2 peak. The desorption of O2 from the surface, which resulted in a decrease in the CL intensity is attributed to the dissociation of SiO2 into elemental Si and O by the electron bombardment. The degradation was less severe at higher oxygen pressures. PbSO4 was also formed on the surface during the electron beam degradation process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Thin film diffusion studies often involve a surface-sensitive analysis technique combined with ion erosion to produce a depth profile of a sample. Such studies compare the depth profile of a reference sample to the depth profiles of samples that were annealed at different temperatures and times. The extent to which atoms of one layer diffuse into an adjacent layer, for a particular temperature and time, yields information on the diffusion process involved and allows quantification of the diffusion coefficient. The drawback to using an erosion-type system is the effect of the incident ions on the surface being probed. The Mixing-Roughness-Information model attempts to compensate for this effect and is often employed as a means of quantification of measured depth profiles by means of profile reconstruction. Used in conjunction with Auger electron spectroscopy, the Mixing-Roughness-Information (MRI) model is a useful tool to reconstruct the ion erosion depth profiles as well as extracting interdiffusion parameters from these depth profiles. This study focuses on the extraction of the diffusion coefficient of Ni in Cu from Ni/Cu depth profiles obtained from ion erosion Auger electron spectroscopy. The resultant depth profiles were reconstructed with the MRI model. The diffusion coefficient for Ni diffusing in Cu was obtained from the MRI fit and it compared well to values available in literature.

Interdiffusion parameters are often extracted from depth profiles of the interface of annealed thin films by measuring the annealing time of the sample as well as the distance over which interdiffusion took place. The annealing time is usually taken as the time from the moment the sample enters the oven to the exact moment the sample is removed from the oven. However, diffusion does not start and stop at these points, as the temperature of the sample does not change instantaneously. Any calculation performed with the instantaneous and therefore erroneous time will result in incorrect diffusion parameters extracted from the depth profiles. The influence of the extended heating period is studied by solving Fick's second law numerically and employing three distinct heating profiles in the calculations, namely instantaneous, actual, and linear. The results indicate a clear difference between the first two calculated depth profiles. Using these calculations and some experimental results, a method that employs linear heating and cooling of a sample is proposed for studying the interdiffusion of fast diffusing elements (with low activation energies).