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.