Nudging or ‘choice architecture’ refers to strategic changes in the environment that are anticipated to alter people’s behaviour in a predictable way, without forbidding any options or significantly changing their economic incentives. Nudging strategies may be used to promote healthy eating behaviour. However, to date, the scientific evidence has not been systematically reviewed to enable practitioners and policymakers to implement, or argue for the implementation of, specific measures to support nudging strategies. This systematic review investigated the effect of positional changes of food placement on food choice. In total, seven scientific databases were searched using relevant keywords to identify interventions that manipulated food position (proximity or order) to generate a change in food selection, sales or consumption, among normal-weight or overweight individuals across any age group. From 2576 identified articles, fifteen articles comprising eighteen studies met our inclusion criteria. This review has identified that manipulation of food product order or proximity can influence food choice. Such approaches offer promise in terms of impacting on consumer behaviour. However, there is a need for high-quality studies that quantify the magnitude of positional effects on food choice in conjunction with measuring the impact on food intake, particularly in the longer term. Future studies should use outcome measures such as change in grams of food consumed or energy intake to quantify the impact on dietary intake and potential impacts on nutrition-related health. Research is also needed to evaluate potential compensatory behaviours secondary to such interventions.

The morphology of nanocrystalline (nc)-Si/amorphous (a)-SiO2 superlattices (SLs) is studied using Raman spectroscopy in the acoustic and optical phonon ranges, transmission electron microscopy (TEM), and atomic force microscopy (AFM). It is demonstrated that high temperature annealing (up to 1100°C) and oxidation in O2/H2O ambient do not destroy the SL structure, which retains its original periodicity and nc-Si/a-SiO2 interface abruptness. It is found that oxidation at high temperatures reduces the defect density in nc-Si/a-SiO2 SLs and induces the lateral coalescence of Si nanocrystals (NCs). The size, shape, packing density, and crystallographic orientation of the Si nanocrystals are studied as a function of the oxidation time.

We use Raman spectroscopy to study the size, shape and crystallographic orientation of silicon nanocrystals formed by solid phase crystallization of amorphous Si/SiO2 superlattices (SLs) grown by radio-frequency sputtering. The first and second Raman peaks broadening, their relative positions and intensities indicate the presence of nanoscale Si objects with a degree of disorder (grain boundaries) and strain (Si/SiO2 interfaces). Shapes of Si nanocrystals sandwiched between SiO2 layers strongly influence the Si/SiO2 interface roughness, which is inferred from the intensities of folded acoustic phonon scattering. The averaged crystallographic orientation of Si nanocrystals is determined by polarized Raman analysis. The laterally elongated nanocrystals exhibit <111> preferred crystallographic orientation along the SL axis due to orientation-dependent crystallization rates. These results demonstrate that control over Si nanocrystals structural parameters has been achieved and that solid phase crystallization of nanometer-thick amorphous Si films remains one of the most promising techniques for Si-based nanoelectronic device fabrication.

A UHV MBE apparatus in which the deposition of both group IV and group III-V components is possible without breaking vacuum has been utilized to compare the growth of GaAs epilayers on non-polar Si(100) and Ge coated Si(100) substrates. In addition, a comparison of GaAs epilayers grown on substrates cleaned by ex-situ techniques and on substrates given all UHV in-situ surface preparation was made. Defect reduction by the incorporation of strained-layer superlattice dislocation filters and by post-growth rapid thermal anneal (RTA) thermal cycles was also investigated. Optical and material properties comparable to MBE grown GaAs/GaAs were obtained for GaAs grown on Ge coated Si(100) substrates.

Si/Ge/Si (100) structures consisting of a thin epitaxial layer of Ge (1-64 monolayers) on Si and covered with a 5 nm overlayer of epitaxial Si were grown by MBE. The layers were analyzed by Rutherford backscattering(RBS)-channeling and transmission electron microscopy (TEM). For structures containing 4 or 8 monolayers of Ge, the channeling <110> angular scans showed unusual features that could be due to imperfect steering of the ion beam in the thin Si overlayer. Cross sectional TEN showed that the Ge epitaxy was good for these Ge thicknesses, but that for an average Ge coverage of 16 monolayers, Ge hillocks up to 90 monolayers thick occurred.

Si1−xGex alloys and multilayers synthesized by solid source MBE on Si(100) substrates have been characterized by low temperature photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). Phonon resolved transitions originating from excitons bound to shallow impurities were observed in addition to a broad band of intense luminescence. PL spectroscopy over the temperature range 2K to 100K has been used to characterize Si1−xGex/Si heterostructures exhibiting both types of PL spectra. Thin alloy layers exhibited phonon-resolved PL spectra, similar to bulk material, but shifted in energy due to strain and hole quantum confinement. In single quantum wells confinement shifts up to ∼200 meV were observed (1.2 nm wells with x = 0.38) and NP linewidths down to 1.37 meV were obtained. However, the broad PL band (peak energy ∼120meV below the strained bandgap) was predominant when the alloy layer thickness was greater than 2 – 10nm, depending on x, growth temperature, and substrate surface preparation. The strength of the broad PL band was correlated with the areal density of strain perturbations (∼109cm−2 per quantum well; local lattice dilation ∼1.5 nm in diameter) observed in plan-view TEM. The role of MBE growth parameters in determining optical properties was investigated by changing growth temperature, substrate preparation procedures and exploring the effect of surface passivation in a hydrogen ambient. In addition, post growth anneals at temperatures in the range 700°C to 1 100°C were carried out, where interdiffusion removes interfacial asperities and the broad luminescence band decays to zero intensity.

Heteroepitaxial (100)CdTe || (100)InSb structures have been fabricated by growing CdTe epilayers, at growth temperatures below 200°C, on single crystal InSb substrates by low-energy bias sputtering. Controlled low-energy ion bombardment at the substrate was employed to clean the growth surface in-situ just prior to film deposition and to modify the growth kinetics and enhance adatom mobility during deposition. Raman spectroscopy of the interface revealed no evidence of In2Te3 and secondary ion mass spectroscopy showed the interface to be chemically abrupt.

A small-angle cleavage technique has been developed for transmission electron microscopy (TEM) of semiconductors and related materials. In this technique, samples are prepared by back-thinning the material to a prescribed thickness, back-scribing the material at a specific angle to a standard cleavage plane, and cleaving along these scribe lines. A second cleave is made along the standard cleavage plane to intersect the first cleave, forming a thin wedge. This wedge is mounted on a grid, providing an electron transparent tip free of ion milling artifacts.

PtSi/Si interfaces have been formed by depositing Pt layers on chemically cleaned, lightly doped, n-type Si (100) wafers in a UHV magnetron sputter-deposition system using ultra high purity Ar as the sputter gas, followed by ex-situ silicidation in N2 ambient utilizing a 3-step rapid thermal annealing (RTA) process. The polycrystalline PtSi layer, with oriented grains ranging in size from 50-100 nm, exhibits a columnar growth morphology. The PtSi/Si interface is planar with interface roughness in the order of 5 nm peak-to-peak. Auger depth profile shows uniform composition through the PtSi layer and a clean and chemically abrupt PtSi/Si interface.

It has been observed that the sheet resistance of a Ti-salicided polysilicon-gate electrode or source/drain region increases significantly as the dimension reaches the lower sub-micron range. The resistance of platinum and nickel silicide (PtSi and NiSi), however, does not increase with reduced linewidth. We have studied PtSi and NiSi films with deep sub-micron linewidths on single crystal or poly-Si substrates. In this study, the material properties such as sheet resistance, grain structure and surface morphology of these silicide films in confined geometries are reviewed and compared with TiSi2. Process windows for forming and maintaining these silicides are explored.