The metastable heterostructure, (BiSe) 0.97 MoSe 2 , containing alternating bilayers of BiSe and MoSe 2 trilayers was synthesized using the modulated elemental reactant method to determine if charge transfer from BiSe to MoSe 2 would stabilize the metallic 1T polymorph of MoSe 2 . Optimum synthesis conditions were determined by following the structural evolution as a function of temperature. The structure of the product contained distorted rock salt-structured BiSe layers alternating with hexagonal MoSe 2 layers. High-angle annular dark field scanning transmission electron microscopy images revealed that two different polymorphs of MoSe 2 coexisted in (BiSe) 0.97 MoSe 2 . Raman spectroscopy confirmed the presence of 1T MoSe 2 layers. X-ray photoelectron spectroscopy (XPS) indicated that there were two different electronic states for both Mo and Bi. The Mo states are consistent with having octahedral and trigonal prismatic coordination of molybdenum as found in the 1T and 2H polymorphs of MoSe 2 . The two different electronic states for Bi are consistent with the presence of antiphase boundaries in the BiSe layers. Estimating the relative amount of each electronic state from the XPS spectra indicates that the percentage of 1T MoSe 2 is about 40%, whereas the amount of Bi 3+ in the BiSe is approximately 60%. The measured resistivity increases as temperature is decreased, consistent with an activated conduction mechanism with a small activation energy (∼0.05 eV). The temperature stability and low resistivity of (BiSe) 0.97 MoSe 2 make it potentially interesting as a means of improving electrical contacts to MoSe 2 .

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Skutterudites are promising materials for future thermoelectric applications. Whereas the skutterudite CoSb 3 is intensively studied, nearly no investigations for FeSb 3 are performed due to its metastable character and the comparably low decomposition temperature.In this work, single phase FeSb 3 thin films were prepared by co-deposition of Fe and Sb using molecular beam epitaxy at room temperature followed by post-annealing. The transport properties of a Fe-Sb composition series were determined and reveal high power factors S 2 σ up to 14 µW/K 2 cm. Furthermore, the structural parameters, the electronic structure and the transport parameters were calculated by density functional theory giving excellent agreement to the experimental data.

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Hexagonal aluminium nitride (AlN) thin films prepared by the reactive magnetron sputtering method usually undergo post-growth annealing treatment aimed at the improvement of crystalline quality as a principal step for their performance as piezoelectric transducers in micro-electro-mechanical systems. Herein, the post-growth annealing of AlN films deposited on Si (111) is investigated by Raman and Fourier transform infrared spectroscopies, X-ray diffraction, and scanning probe microscopies. The thermally treated films show a positive trend in stress relaxation via annealing up to 1200 C; however, it is accompanied by a dewetting of the quasi-epitaxial layer and the formation of the cubic AlN phase. The critical role is played by the AlN/Si interface being sensitive to oxidation via interstitial oxygen in Si wafers. The piezoelectric performance of the AlN/Si system is found to be inversely proportional to the post-growth annealing temperature.

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The effect of flash-lamp annealing (FLA) on the re-crystallization of thin films made of colloidal Cu2ZnSnS4 nanocrystals (NCs) is investigated by Raman spectroscopy. Unlike similar previous studies of NCs synthesized at high temperatures in organic solvents, NCs in this work, which have diameters as small as 2–6 nm, were synthesized under environmentally friendly conditions in aqueous solution using small molecules as stabilizers. We establish the range of FLA conditions providing an efficient re-crystallization in the thin film of NCs, while preserving their kesterite structure and improving their crystallinity remarkably. The formation of secondary phases at higher FLA power densities, as well as the dependence of the formation on the film thickness are also investigated. Importantly, no inert atmosphere for the FLA treatment of the NCs is required, which makes this technology even more suitable for mass production, in particular for printed thin films on flexible substrates.

Relatively high temperatures even up to 500 °C are required to obtain bismuth vanadate (BiVO4) films with the scheelite monoclinic (s‐m) structure that shows the highest photocatalytic activity. This requirement limits the possible choice of substrates. Moreover, high quality thin layers of crystalline BiVO4 cannot be prepared with current methods. In this study a light‐induced crystallization approach is presented, which is a step toward preparation and patterning of BiVO4 (s‐m) films for applications on plastic substrates. Thin films of amorphous BiVO4 are prepared by pulsed laser deposition. The possibility of using green (514.7 nm) laser illumination for crystallization of BiVO4 is investigated. The laser‐induced phase transition is tracked using Raman spectroscopy. The results are compared with those obtained from thermally annealed samples, crystalline structure of which is confirmed by measuring X‐ray diffraction. The homogeneity and quality of crystallization are verified using micro‐Raman spectroscopy imaging, while time‐dependent experiments reveal the crystallization rate. The conductivity of the crystallized region is investigated using conductive atomic force microscopy. A strong increase in the conductivity is found in the patterned regions. Experimental results demonstrate the possibility of using the laser‐induced crystallization of BiVO4 to prepare patterns of improved conductivity and semiconducting properties in comparison to amorphous surroundings.