Transition metal dichalcogenides (TMDCs) are attractive for variety of nanoscale electronics and optoelectronics devices due to their unique properties. Despite growing progress in the research field of TMDCs, many of their properties are still unknown. In this letter, we report measurements of Raman spectra of rhenium diselenide (ReSe₂) and tin diselenide (SnSe₂) layered semiconductor nanosheets as a function of temperature (70–400 K). We analyze the temperature dependence of the positions of eight ReSe₂ modes and SnSe₂ A_1g mode. All observed Raman mode shifts exhibit nonlinear temperature dependence at low temperatures which is explained by optical phonon decay process into two or three acoustics phonons. The first order temperature coefficients (χ), determined for high temperatures, of rhenium diselenide Raman modes are in the range between −0.0033 and −0.0118 cm⁻¹/K, whereas χ of tin diselenide A_1g mode was −0.0129 cm⁻¹/K. Our findings are useful for further analysis of phonon and thermal properties of these dichalcogenide layered semiconductors.

Increasing the requirements on telecommunications systems such as the need for higher data rates and connectivity via the Internet of things results in continuously increasing amounts of electromagnetic radiation in ever-higher telecommunications bands (up to terahertz). This can generate unwanted electromagnetic radiation that can affect the operation of electronic devices and human health. Here, we demonstrate that nonconductive and lightweight, graphene-based composites can shield more than 99.99% of the electromagnetic energy in the sub-THz range mainly via absorption. This contrasts with state-of-the-art electromagnetic radiation shielding materials that simply redirect the energy of the radiation from a protected area via conduction-based reflection mechanisms. This shifts the problem of electromagnetic pollution from one place to another. We have demonstrated that the proposed composites can be fabricated by industrial compatible methods and are characterized by specific shielding efficiency values that exceed 30 dB cm³ g⁻¹, which is more than those for typical metals used today. Therefore these materials might help to solve the problem of electromagnetic environmental pollution.

Three samples with dielectric layers from high‐κ dielectrics, hafnium oxide, gadolinium‐silicon oxide, and lanthanum‐lutetium oxide on silicon substrate were studied by Raman spectroscopy. The results obtained for high‐κ dielectrics were compared with spectra recorded for silicon dioxide. Raman spectra suggest the similarity of gadolinium‐silicon oxide and lanthanum‐lutetium oxide to the bulk nondensified silicon dioxide. The temperature treatment of hafnium oxide shows the evolution of the structure of this material. Raman spectra recorded for as-deposited hafnium oxide are similar to the results obtained for silicon dioxide layer. After thermal treatment especially at higher temperatures (600°C and above), the structure of hafnium oxide becomes similar to the bulk non‐densified silicon dioxide.