Charge transport and electroluminescence mechanisms in Si-rich Si oxynitride/silicon oxide (SRON/SiO2) superlattices deposited on p-type Si substrate are reported. The superlattice structures were deposited by plasma-enhanced chemical-vapor deposition and subsequently annealed at 1150 °C to precipitate and crystallize the Si excess into Si nanocrystals. The dependence of the electrical conduction on the applied voltage and temperature was found to be well described by a Poole-Frenkel transport mechanism over a wide voltage range. On the other hand, the observed dependence of the electroluminescence on the SRON layer thickness is a clear proof of quantum confinement and was attributed to an excitonic radiative recombination taking place in the confined states within the Si quantum dots. A model is proposed based on thermal hopping of electrons between the quantum dots acting as trap states (Poole-Frenkel). A correlation between carrier transport and electroluminescence has been established considering impact ionization of high-kinetic energy electrons on the Si quantum dots

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Over the last decades, significant progress has been made in inorganic materials to enable them as next generation photovoltaic materials that can fulfil the green energy requirements. Cu2ZnSn(S,Se)4 stands out...

We report a joint experimental and theoretical study of the lattice dynamics of cubic Tb2O3. Up to 16 optical Raman‐active modes have been observed with polarized and unpolarized Raman scattering measurements on a high‐quality Tb2O3 single crystal. The measured wavenumbers have been compared with those of other rare‐earth (RE) and related sesquioxides with cubic (C‐type or bixbyite) structure. First‐principles calculations have allowed us to assign the symmetry of the experimentally observed Raman‐active modes. Additional lattice‐dynamical calculations on the related cubic RE sesquioxides Dy2O3, Gd2O3, Eu2O3, and Sm2O3 indicate that the phonon wavenumbers of the Raman‐active modes in these compounds are monotonically reduced with increasing the lattice parameter along the Dy2O3‐Tb2O3‐Gd2O3‐Eu2O3‐Sm2O3 series, thus prompting for a revision of the experimental Raman spectra of some of these compounds (mainly Eu2O3 but also Gd2O3).