![]() ; ; et al in Physical Review. B, Condensed Matter and Materials Physics (2013), 88(11), 115313 We have investigated the diameter dependence of the Raman spectra of lead selenide nanocrystals. The first-order Raman peak at about 136 cm−1 and its second-order overtone at twice this wavenumber move up ... [more ▼] We have investigated the diameter dependence of the Raman spectra of lead selenide nanocrystals. The first-order Raman peak at about 136 cm−1 and its second-order overtone at twice this wavenumber move up in energy with decreasing nanocrystal diameter. This anomalous behavior is interpreted in terms of quantum confinement of the longitudinal optical (LO) phonon whose frequency displays a minimum at in the dispersion of bulk PbSe. We perform ab initio calculations of the phonons of PbSe slabs with up to 15 layers. The LO mode perpendicular to the slab shifts indeed upwards with decreasing layer thickness, thus validating the interpretation of the anomalous radius dependence of the Raman spectra in terms of quantum confinement. [less ▲] Detailed reference viewed: 159 (2 UL)![]() ; ; et al in International Journal of Nanotechnology (2008), 5(6-8), 631-648 This paper gives an overview over the fundamental research in nanosciences at the Institute of Electronics, Microelectronics and Nanotechnology (IEMN). We present some highlights from the numerical ... [more ▼] This paper gives an overview over the fundamental research in nanosciences at the Institute of Electronics, Microelectronics and Nanotechnology (IEMN). We present some highlights from the numerical simulation of the electronic structure of nanowires and nanotubes, the charge spectroscopy of Si nanoparticles and C nanotubes, the scanning tunnelling spectroscopy of semiconductor quantum dots, to research in surface science for bio-screening. [less ▲] Detailed reference viewed: 128 (2 UL) |
||