Measurement of phonon pressure coefficients for a precise determination of deformation potentials in SiGe alloys

Abstract

Stable, ultrathin micropatterns containing CdS nanoparticles (CdS‐NPs) were fabricated in a two‐step process. In the first step, a precursor film was built‐up by the layer‐by‐layer electrostatic self‐assembly of photosensitive nitro‐diazoresin and mercaptoacetic acid capped CdS nanoparticles. In the second step, the film was selectively exposed to UV light through a photomask and developed in an aqueous solution of sodium dodecylsulfate (SDS). The formation of covalently linked micropatterns was based on the different solubilities of the irradiated and non‐irradiated parts of the film in the developer. Namely, the irradiated regions were cross‐linked and insoluble, whereas the non‐irradiated regions, linked with ionic bonds, were removed by the SDS solution. The resultant patterns were systematically characterized with atomic force microscopy, field emission scanning electron microscopy, optical microscopy, and X‐ray photoelectron spectroscopy.

Influence of alloy inhomogeneities on the determination by Raman scattering of composition and strain in Si1–xGex/Si(001) layers

“…In principle, a single measurement in back-scattering geometry should be enough for a precise determination of the composition of the layers given the in-plane strain, or vice versa. This approach has been already applied by several authors to strained SiGe layers, [16][17][18][19][20][21][22][23][24][25] pointing in their work to the difficulties encountered in some situations to attain the desired accuracy. Although the underlying mathematics employed to extract composition and/or strain values from the measured Raman spectra is extremely simple, a cumbersome interrelation between the involved physical parameters easily leads to misinterpretation of the experimental results.…”