Roland Gillen

Photoluminescence of freestanding single- and few-layerMoS2

We present a photoluminescence study of freestanding and Si/SiO2 supported single- and few-layer MoS2. The single-layer exciton peak (A) is only observed in freestanding MoS2. The photoluminescence of supported single-layer MoS2 is instead originating from the A- (trion) peak as the MoS2 is n-type doped from the substrate. In bilayer MoS2, the van der Waals interaction with the substrate is decreasing the indirect band gap energy by up to ~ 80 meV. Furthermore, the photoluminescence spectra of suspended MoS2 can be influenced by interference effects.

Nature of the electronic band gap in lanthanide oxides

Accurate electronic structures of the technologically important lanthanide/rare-earth sesquioxides (Ln2O3, with Ln=La, ⋯,Lu) and CeO2have been calculated using hybrid density functionals HSE03, HSE06, and screened exchange (sX-LDA). We find that these density functional methods describe the strongly correlated Ln f electrons as well as the recent G0W0@LDA+U results, generally yielding the correct band gaps and trends across the Ln period. For HSE, the band gap between O 2p states and lanthanide 5d states is nearly independent of the lanthanide, while the minimum gap varies as filled or empty Ln 4f states come into this gap. sX-LDA predicts the unoccupied 4f levels at higher energies, which leads to a better agreement with experiments for Sm2O3, Eu2O3, and Yb2O3.

Few-Layer Antimonene by Liquid-Phase Exfoliation

Abstract We report on a fast and simple method to produce highly stable isopropanol/water (4:1) suspensions of few‐layer antimonene by liquid‐phase exfoliation of antimony crystals in a process that is assisted by sonication but does not require the addition of any surfactant. This straightforward method generates dispersions of few‐layer antimonene suitable for on‐surface isolation. Analysis by atomic force microscopy, scanning transmission electron microscopy, and electron energy loss spectroscopy confirmed the formation of high‐quality few‐layer antimonene nanosheets with large lateral dimensions. These nanolayers are extremely stable under ambient conditions. Their Raman signals are strongly thickness‐dependent, which was rationalized by means of density functional theory calculations.

Band structure calculations of CuAlO 2 , CuGaO 2 , CuInO 2 , and CuCrO 2 by screened exchange

We report density functional theory band structure calculations on the transparent conducting oxides CuAlO

Fundamental Insights into the Degradation and Stabilization of Thin Layer Black Phosphorus

{}_{2}

Interlayer resonant Raman modes in few-layerMoS2

, CuGaO

Indirect doping effects from impurities in MoS2/h-BN heterostructures

{}_{2}

Symmetry properties of vibrational modes in graphene nanoribbons

, CuInO

Electrical conduction of carbon nanotube forests through sub-nanometric films of alumina

{}_{2}

Electron spin resonance signature of the oxygen vacancy in HfO2

, and CuCrO