Influence of phonon anharmonicity on Raman spectra of CuZnSn(S,Se) polycrystalline thin films through computational study.

CuZnSn(S,Se) (CZT(S,Se)) thin films exhibit the characteristics necessary to be effective absorbers in solar cells. In this report, the room temperature experimental Raman scattering spectra, recorded at different excitation wavelengths, are systematically analyzed theoretically using the results of DFT harmonic frequencies calculations at the Γ-point for various modifications of kesterite (KS), stannite (ST), and pre-mixed Cu-Au (PMCA) crystal structures. The specific anharmonism-induced features in the spectra of CZT(S,Se) crystals are identified, and the spectral lineshapes at varied strengths of anharmonic interaction are simulated.

Modified rigorous coupled-wave analysis for grating-based plasmonic structures with a delta-thin conductive channel: far- and near-field study.

The modified rigorous coupled-wave analysis technique is developed to describe the optical characteristics of the plasmonic structures with the grating-gated delta-thin conductive channel in the far- and near-field zones of electromagnetic waves. The technique was applied for analysis of the resonant properties of AlGaN/GaN heterostructures combined with a deeply subwavelength metallic grating, which facilitates the excitation of the two-dimensional plasmons in the terahertz (THz) frequency range. The convergence of the calculations at the frequencies near the plasmon resonances is discussed.

Electronic edge-state and space-charge phenomena in long GaN nanowires and nanoribbons.

We studied space-charge-distribution phenomena in planar GaN nanowires and nanoribbons (NRs). The results obtained at low voltages demonstrate that the electron concentration changes not only at the edges of the NR, but also in the middle part of the NR. The effect is stronger with decreasing NR width.