Nanostructure characterization of Co–Pd–Si–O soft magnetic nanogranular film using small-angle X-ray and neutronscattering

The nanostructure of a Co–Pd–Si–O nanogranular film was investigated with the combined use of small-angle x-ray (SAXS) and neutron scattering (SANS). Using a new, compact type of SANS instrument, the SANS profiles of individual particles with a diameter of about 2–4 nm were successfully observed. The structures of magnetic regions were found to be the same as the chemical structures of the particles, and a sharp interface was observed between the matrix and the particles. The SAXS to SANS ratio clearly indicates that the particles are a CoPd alloy and the matrix is not pure SiO2. In fact, the matrix is composed of a meaningful amountof Co

Microstructural investigation of inkjet printed Cu(In,Ga)Se2 thin film solar cell with improved efficiency

Inkjet printed copper indium gallium diselenide (CIGS) thin film solar cell has attracted tremendous attention because of its various technological benefits as a non-vacuum process. Focused efforts in selenization of inkjet printed films to make the process feasible, are desired. In this work, microstructural investigation of inkjet printed precursor film selenized by rapid thermal processing (RTP) is presented. The optimization of selenization time for transforming metal nitrates precursor ink to CIGS thin film is investigated. Based on the results, the growth mechanism to form CIGS from inkjet printed CIG precursor films is proposed. Systematic study on the molybdenum diselenide (MoSe2) phase evolution during the two-step atmospheric pressure selenization process at the CIGS-Mo interface and its effect on device performance are carried out. Non-uniform inter-diffusion of indium (In) and gallium (Ga) during selenization, resulting in double-layered CIGS, one of the major reason limiting the performance of the devices is investigated through XRD, Raman, FESEM, EDS and Mott-Schottky analysis. The significant improvement in device efficiency from 0.4% to 4.2% is achieved due to microstructural improvement in CIGS films. Investigation on the mechanism of microstructural growth with selenization time affecting final device performance is presenting in this work

Strengthening mechanisms in Fe-Al based ferritic low-density steels

Low-density steels with different aluminium contents have been investigated with an aim to examine the occurrence of different strengthening mechanisms leading to its higher strength. A composition corresponding to 6.8 wt% aluminium has been studied to understand the underlying strengthening mechanisms. Different factors contributing to the strengthening mechanisms have been separately analyzed. Microstructural features have been analyzed using Mossbauer spectroscopy, small angle X-ray scattering (SAXS), X-ray line profile analysis and transmission electron microscopy (TEM). The enhanced yield strength of the low-density steel containing 6.8 wt % Al was attributed to the strengthening effects arising from the ferrite grain size, dislocations incorporated during processing, ordered phase formation and the presence of Al atoms in the solid solution. Each of these operating mechanisms was modelled by using its constitutive equation for example, grain size strengthening by classical Hall-fetch equation and the strengthening from dislocations by Taylor's equation. In addition, the formation of nano-sized ordered phase was evaluated by TEM, Mossbauer spectroscopy, SAXS and hence order strengthening was modelled by using the size and volume fraction (as determined by TEM and SAXS). Strengthening due to lattice frictional stress required for dislocation motion was also incorporated into the model