Local phonon imaging of AlN nanostructures with nanoscale spatial resolution.

We demonstrate local phonon analysis of single AlN nanocrystals by two complementary imaging spectroscopic techniques: tip-enhanced Raman scattering (TERS) and nano-Fourier transform infrared (nano-FTIR) spectroscopy. Strong surface optical (SO) phonon modes appear in the TERS spectra with their intensities revealing a weak polarization dependence. The local electric field enhancement stemming from the plasmon mode of the TERS tip modifies the phonon response of the sample, making the SO mode dominate over other phonon modes.

Malignant Endo-suprasellar Glioma: A Case Report and a Brief Review of the Literature.

Introduction: Malignant sellar gliomas are very rare phenomena. To date, only few cases of sellar and suprasellar glioblastomas have been reported, most of which originate from the optic nerve or optic chiasm.

Case Presentation: We present a 34-year-old woman with malignant endo-suprasellar glioma, originating from the pituitary stalk, which was initially classified as a macroprolactinoma.

Crystal Structure and Predominant Defects in CdS Quantum Dots Fabricated by the Langmuir-Blodgett Method.

The crystal structure and shape of the CdS quantum dots (QDs) obtained by the Langmuir-Blodgett method were studied by transmission electron microscopy, extended X-ray absorption fine structure spectroscopy (EXAFS), and ultraviolet spectroscopy. X-ray photoelectron spectroscopy (XPS) and stationary photoluminescence spectroscopy (PL) methods were used to determine the dominant surface defects. Initially synthesized QDs within the Langmuir-Blodgett film of fatty behenic acid have a cubic structure and oblate spheroid shape, while free-standing QDs obtained after the matrix evaporation have a wurtzite structure and sphere-like shape.

The effect of barrier layers on 2D electron effective mass in AlGaN/AlN/GaN heterostructures.

The Shubnikov de Haas (SdH) effect measurements have been performed to evaluate the influence of SiNpassivation, a spacer layer, and Si-doped barrier layer on the electronic transport parameters of two-dimensional (2D) electrons in AlGaN/AlN/GaN heterostructures under temperatures from 1.8 K to 40 K and at a magnetic field up to 11 T. The 2D electron effective mass (*), 2D carrier density (), the difference between Fermi level and subband energy levels (-), quantum lifetime () are determined by analyzing SdH oscillations.