We report a direct observation of Al penetration into an organic film of 8-hydroxyquinoline aluminum (Alq) in a Alq/Al bilayer, a common interface occurring in many organic light-emitting diode structures. The Al penetration has a strong correlation with Alq photoluminescence quenching. We also demonstrate that the penetration and luminescence quenching can be effectively suppressed by ∼20 Å of an intervening layer of Al2O3 at the Alq/Al interface.

Silicon carbide (4H) based metal–oxide–semiconductor field-effect transistors provide capabilities in high power and high temperature inaccessible to silicon. However, the performance of thermally grown oxide-based devices remains limited by oxide/semiconductor interface defects. This research employs deposited dielectrics, Al₂O₃, rather than thermal oxidation. Investigation of various pre-deposition processes reveals different degrees of improvements in the electronic properties. An optimum structure employs the preparation of a nitrided surface via NO annealing, a process known to passivate surface defects, a hydrogen exposure, followed by Al₂O₃ deposition. Inversion layer field-effect mobilities as high as 52 cm²/V s are reported in the optimum structures. Capacitance–voltage measurements and field-effect mobility characteristics indicate a trapping limited conductivity in Al₂O₃/4H-SiC inversion channels similar to SiO₂/4H-SiC. Leakage currents and interface breakdown are also reported for various Al₂O₃/4H-SiC MOS structures.

Decay dynamics of local vibrational modes provides unique information about energy relaxation processes to solid-state phonon bath. In this Letter the lifetimes of the asymmetric stretch mode of interstitial ${}^{16}\mathrm{O}$ and ${}^{17}\mathrm{O}$ isotopes in Si are measured at 10 K directly by time-resolved, transient bleaching spectroscopy to be 11.5 and 4.5 ps, respectively. A calculation of the three-phonon density of states shows that the ${}^{17}\mathrm{O}$ mode lies in the highest phonon density resulting in the shortest lifetime. The lifetime of the ${}^{16}\mathrm{O}$ mode in Ge is measured to be 125 ps, i.e., $\sim 10$ times longer than in Si. The interaction between the local modes and the lattice vibrations is discussed according to the activity of phonon combinations.

Characterization of the atomic level processes that determine optical transitions in emerging materials is critical to the development of new platforms for classical and quantum networking. Such understanding often emerges from studies of the temperature dependence of the transitions. We report measurements of the temperature dependent Er³⁺ photoluminescence in single crystal Er₂O₃ thin films epitaxially grown on Si(111) focused on transitions that involve the closely spaced Stark-split levels. Radiative intensities are compared to a model that includes relevant Stark-split states, single phonon-assisted excitations, and the well-established level population redistribution due to thermalization. This approach, applied to the individual Stark-split states and employing Er₂O₃ specific single-phonon-assisted excitations, gives good agreement with experiment. This model allows us to demonstrate the difference in the electron-phonon coupling of the ⁴S_3/2 and ²H_11/2 states of Er³⁺ in E₂O₃ and suggests that the temperature dependence of Er³⁺ emission intensity may vary significantly with small shifts in the wavelength (~0.1 nm) of the excitation source.