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Emergent exotic phenomena in the self-assembled process of vertically aligned nanocomposite (VAN) thin film remain under intensive studies. Insight exploration on the self-assembled formation from the combination of two different phases of materials is not only important to optimize the physical properties yields from those combined materials, but also open up a new avenue to discover new materials with the VAN system. In this work, the thermodynamic control of the self-assembled formation of BiFeO3-CoFe2O4 (BFO-CFO) VAN thin film has been confirmed by studying the effects of substrate temperature during the growth process by pulsed laser deposition (PLD) technique. The structural examination results on the samples, which were growing with various substrate temperatures highlight the importance of the thermodynamic factor to control the crystalline structure of BFO phase and CFO pillar size, which then affect the physical properties and further its practical applications. For instance, we can control the size of the CFO pillar using a temperature substrate to find appropriate spin magnetic switching in the CFO pillar for memory device applications. This study also sheds light on the relationship between thermodynamics and elastic strain energy on the formation of self-assembled matrix-pillars of the BFO-CFO VAN which is important for device fabrication. [ABSTRACT FROM AUTHOR]

Ho monopnictides (HoPn: Pn = N, P, As, Sb, and Bi) and monochalcogenides (HoCh: Ch = S, Se, and Te) are known to possess a nontrivial magnetic structure, while solid-phase HoO has not been synthesized yet. In this study, a rock salt-type HoO epitaxial thin film was grown by using the pulsed laser deposition method, which had a bandgap of 0.11 eV and tunable electrical conduction via its oxygen nonstoichiometry. Its Curie temperature, above 130 K, was much higher than those of HoPn and HoCh, most likely due to an enhanced direct exchange interaction. Similar to HoPn and HoCh, a HoO thin film showed a metamagnetic behavior below the Curie temperature in spite of its dominant ferromagentic ordering. [ABSTRACT FROM AUTHOR]

The design and development of the next-generation power-efficient CIGS solar cells are at the research forefront due to their potential applications in renewable energy. Due to rich fundamental properties such as chemical and physical structures of the CIGS layer, cell scaffolding, and its promising applications like low cost, easy integration, and high efficiency, the CIGS-based solar cell systems are of considerable interest and received tremendous attention. In this article, we review the CIGS solar cells from the point of view of structural engineering. We explain the intrinsic parts of crystalline, optical, and electronic structures of the CIGS absorber layer up to the extrinsic part of the cell multilayer structure. For intrinsic structure, we primarily review the modification of the crystallinity or chemical composition of the CIGS and the effects that these modifications have on the physical properties such as the adjustment of the bandgap grading, effect of impurity or doping, selenization, oxidation processes, and the surface morphology and structure orientation. For extrinsic structure, the effect of substrates, electrical back contact, windows, n -buffer, grid, and antireflection layers will be discussed further, as well as the possibility of their tandem use with other solar cell thin films. [ABSTRACT FROM AUTHOR]