This is the post-peer reviewed version of the following article: A. Castellanos-Gomez et al. “Isolation and characterization of few-layer black phosphorus”. 2D Matererials, 2014, 1(2) 025001 doi:10.1088/2053-1583/1/2/025001 Which has been published in final form at: http://iopscience.iop.org/2053-1583/1/2/025001

/pdf/isolation-and-characterization-of-few-layer-black-phosphorus-4c0wcl7ptc.pdf

Isolation and characterization of few-layer black phosphorus

Numerical studies of amorphous Si show that the lowest 4% of vibrational modes are piane wave like (‘propagons’) and the highest 3% of modes are localized (‘locons’). The rest are neither piane wave like nor localized. We cali them ‘diffusons’. Since diffusons are by far the most numerous, we try to characterize them by calculating such properties as the wave-vector and polarization (which do not seem to be useful), ‘phase auotient’ (a measure of the change of vibrational phase between first-neighbour atoms), spadal polarization memory and diffusivity. Localized states are characterized by finding decay lengths, inverse participation ratios and coordination numbers of the participating atoms.

Diffusons, locons and propagons: Character of atomie yibrations in amorphous Si

Energy transfer from photoexcited zero-dimensional systems to metallic systems plays a prominent role in modern day materials science. A situation of particular interest concerns the interaction between a photoexcited dipole and an atomically thin metal. The recent discovery of graphene layers permits investigation of this phenomenon. Here we report a study of fluorescence from individual CdSe/ZnS nanocrystals in contact with single- and few-layer graphene sheets. The rate of energy transfer is determined from the strong quenching of the nanocrystal fluorescence. For single-layer graphene, we find a rate of approximately 4 ns(-1), in agreement with a model based on the dipole approximation and a tight-binding description of graphene. This rate increases significantly with the number of graphene layers, before approaching the bulk limit. Our study quantifies energy transfer to and fluorescence quenching by graphene, critical properties for novel applications in photovoltaic devices and as a molecular ruler.

http://absimage.aps.org/image/MAR10/MWS_MAR10-2009-006247.pdf

Resonant Energy Transfer from Individual Semiconductor Nanocrystals to Graphene

We present the synthesis of a two-dimensional polymer at the air/water interface and its nm-resolution imaging. Trigonal star, amphiphilic monomers bearing three anthraceno groups on a central triptycene core are confined at the air/water interface. Compression followed by photopolymerization on the interface provides the two-dimensional polymer. Analysis by scanning tunneling microscopy suggests that the polymer is periodic with ultrahigh pore density.

Large Area Synthesis of a Nanoporous Two-Dimensional Polymer at the Air/Water Interface

About 1.5-um-thick single-layer TiN, CrN, TiAlN coatings and nanolayered TiN/CrN, TiAlN/CrN multilayer coatings were deposited on silicon (111) substrates using a13; reactive direct current magnetron sputtering process. Structural characterization of the coatings was done using x-ray diffraction (XRD) and micro-Raman spectroscopy. All13; the coatings exhibited NaCl B1 structure in the XRD data. Raman spectroscopy data of as-deposited coatings exhibited two broad bands centered at 230x2013;250 and 540x2013;630 cmx2212;1.13; These bands have been assigned to acoustical and optical phonon modes, respectively. Thermal stability of the coatings was studied by heating the coatings in air in a13; resistive furnace for 30 min in the temperature range 400x2013;900 xB0;C. Structural changes as a result of heating were characterized using Raman spectroscopy and XRD. Raman13; data showed that TiN, CrN, TiN/CrN, TiAlN, and TiAlN/CrN coatings started to oxidize at 500, 600, 750, 800, and 900 xB0;C, respectively. To isolate the oxidation-induced spectral changes as a result of heating of the coatings in air, samples were also annealed in vacuum at 800 xB0;C under similar conditions. The Raman data of vacuum-annealed coatings showed no phase transformation, and intensity of the optical phonon mode increased and shifted to lower frequencies. The origin of these spectral changes is discussed in terms of defect structure of the coatings. Our results indicate that the thermal stability of nanolayered multilayer coatings is superior to the13; single-layer coatings.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0884291400087197

Raman spectroscopy studies on the thermal stability of TiN, crN, TiAlN coatings and nanolayered TiN/CrN, TiAlN/CrN multilayer coatings

http://repositorium.sdum.uminho.pt/bitstream/1822/4427/1/TSF_398%282001%29_CrN.pdf

Characterisation of chromium nitride films produced by PVD techniques

https://estudogeral.sib.uc.pt/bitstream/10316/4248/1/filef7813df68f464c849561dd45bfecf843.pdf

Property change in ZrNxOy thin films: effect of the oxygen fraction and bias voltage

Single-layered zirconium oxynitride (ZrN x O y ) thin films have been deposited on steel substrates, at a constant temperature of 300 °C, by radiofrequency (rf) reactive magnetron sputtering of a pure Zr target in an argon–oxygen–nitrogen atmosphere. The variation of the flow rate of the reactive gases enabled changes in the composition and structure of the films. X-ray diffraction (XRD) and glancing incidence X-ray diffraction (GIXRD) were used to study the as-deposited films and their structural changes during or after heat treatment, from 400 to 900 °C, in controlled atmosphere and in vacuum. The as-deposited films revealed the occurrence of a face-centred cubic (fcc) phase (Zr–N type), but a Zr–N oxygen-doped phase (Zr–N–O) may be also present depending on the oxygen content in the films. Heat treatment above 600 °C reveals the appearance of a tetragonal phase of zirconium oxide. The results are discussed as a function of the chemical composition of the films, annealing temperature, and type of the annealing process.

/pdf/structural-evolution-in-zrnxoy-thin-films-as-a-function-of-5946gesrsp.pdf

Structural evolution in ZrNxOy thin films as a function of temperature

http://repositorium.sdum.uminho.pt/bitstream/1822/5763/1/TSF_515%282006%29_ZrN.pdf

Raman spectra and structural analysis in ZrOxNy thin films

https://recipp.ipp.pt/bitstream/10400.22/3479/4/ART_DCristea_2013_DFI.pdf

C. Moura

Papers

Characterisation of chromium nitride films produced by PVD techniques

Property change in ZrNxOy thin films: effect of the oxygen fraction and bias voltage

Structural evolution in ZrNxOy thin films as a function of temperature

Raman spectra and structural analysis in ZrOxNy thin films

Properties of tantalum oxynitride thin films produced by magnetron sputtering: The influence of processing parameters