The stress evolution of sputter deposited Mo/Si multilayers of possible application as extreme ultraviolet light mirrors has been investigated by in situ substrate curvature measurements using a multiple parallel laser beam technique. Our preliminary results show well-defined stress modulation concurrent with the deposition of Mo and Si layers in the multilayer structure. Large changes in substrate curvature were measured during the early stages of deposition of the individual layers, with Mo exhibiting apparent tension and Si exhibiting apparent compression. The magnitudes of these curvature changes partially offset each other, resulting in an average compressive stress of −350 MPa in the multilayer. Possible stress generating mechanisms during growth of these multilayers as well as single layer films of Mo and Si will be discussed.

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The interfacial roughness and lateral correlation length of a series of Si/Mo multilayers with bilayer period 69 Å and number of bilayers ranging from 5 to 40 have been characterized by diffuse x-ray scattering. Superlattice peaks are preserved in offset radial scans indicating a high degree of conformality in the roughness. The lateral correlation length increases with total film thickness h as ϳh 0.55 ; however, the magnitude of the roughness is approximately 2 Å for all film thicknesses, in disagreement with scaling laws for self-affine growing surfaces. This observation suggests that interfaces retard the evolution of high-frequency roughness while replicating longer wavelength roughness from one layer to the next

Thin film Cu(In,Ga)Se2 (CIGS) photovoltaic cells are considered to have a high potential for low cost electricity production due to their demonstrated high conversion efficiencies. Various methods have been used to make thin film CIGS solar cells. In the present approach, a low cost roll-to-roll electroplating process is utilized to deposit the CIGS precursor layers. The electroplating technology provides well controlled composition along the length and width of the flexible substrates demonstrating its suitability as a low cost CIGS precursor deposition method. Precursor layers are then subjected to rapid thermal processing to form a photovoltaic-grade CIGS absorber. The processing is done using roll-to-roll production equipment on a flexible metallic substrate. The CIGS based solar cells are fully finished in roll form and then cut into large area cells. The cells are then interconnected to fabricate panels with about 1.1 m 2 aperture area and about 115W power output. These rigid panels show excellent stability under damp heat test conditions and are certified against both UL and IEC standards. More recent work has focused on lightweight flexible solar modules. These modules open new application areas and can further lower the cost of systems by lowering the installation costs. Flexible modules with aperture area efficiency as high as 11.2 % have been demonstrated. Standard module certification tests, including 1000 hour damp heat test, show very small changes of Pmax .

Mechanical properties for two series of amorphous Al–Y–Ni ternary alloys were measured. Both series of alloys can be divided into two distinct groups. Those whose primary crystallization proceeds by growth of quenched-in Al nuclei and those which show a clear glass transition and their crystallization product is more complex. The Young’s modulus, ranging from 82.3 to 45.5 GPa in these series of alloys, is found to be correlated to the crystallization temperature and thermal behavior as well as the crystallization product implying that the mechanical properties depend on the short-range order in the glass.