Ge–Si inverted huts, which formed at the Si∕Ge interface of Si∕Ge superlattice grown at low temperatures, have been measured by X-ray diffraction, grazing incidence X-ray specular and off-specular reflectivities, and transmission electron microscopy (TEM). The surface of the Si∕Ge superlattice is smooth, and there are no Ge–Si huts appearing on the surface. The roughness of the surfaces is less than 3 Å. Large lattice strain induced by lattice mismatch between Si and Ge is found to be relaxed because of the intermixing of Ge and Si at the Si∕Ge interface.

We report spectrally resolved X-ray scattering data from shock compressed foils illustrating the feasibility of X-ray Thomson scattering experiment on a sub-kilo joule laser system. Sandwich targets consisting of CH/Al/CH were shock compressed using ∼1 ns laser pulses. Separate 270 ps laser pulses were used to generate an intense source of Ti-He-α (1s2-1s2p1P) radiation which was used as a probing source of 4.75 keV photons. The spectrum of scattered photons was recorded at a scattering angle of 82° with a CCD fitted spectrometer using a PET crystal in von-Hamos geometry. Although spectral resolution was used to separate the scatter from any background, the resolution was limited by source broadening. The relative level of scatter at different times in the sample history was measured by varying the delay between the shock driving beams and the back-lighter beams. We have compared the scatter spectra with simulations based on two different models of the L-shell bound-free contribution.