Red photoluminescence and blue-shift caused by phase transformation in multilayer films of titanium dioxide and zinc sulfide

The most versatile methods for altering the properties and behavior of materials involve a phase transformation in the solid state. In this article, we report multilayered films of ZnS/TiO2/ZnS on amorphous SiOx/Si substrates by pulsed laser deposition (PLD). After sequential vacuum annealing at various temperatures, we investigated the effects of TiO2 on the phase transformation of ZnS films and the consequential changes in photoluminescence (PL) property. PL spectra of the film revealed red emission centered at 686 nm after annealing at 600°C, however, this emission disappears, and the color shifts to blue after annealing at 700°C. Detailed analysis identified that TiO2 acts as a catalytic agent for the phase transformation of ZnS at this temperature, and that the color shift to blue resulted from decreased red emissions attributed to oxygen in the film. The present results show that catalytic agent-mediated phase transformation has strong potential for the modification of material properties. © 2015 Optical Society of America.1

Ambivalent impact of customer satisfaction on firm value in emerging markets: the case of Korea

Many researchers report that American Customer Satisfaction Index relates significantly and positively to firm value. The purpose of this paper is to examine whether such relation holds in the emerging markets such as Korea. Our preliminary OLS analysis reports that Korean customer satisfaction is irrelevant to firm value. Quantile regressions, applied for further analysis, report that customer satisfaction can be detrimental to firm value if the firm is enjoying the higher kind of value. These results undermine efforts, on the theoretical level, to establish Customer Satisfaction Index as a consolidated firm-value indicator; furthermore, managerial efforts to boost up firm value by managing customer satisfaction lose ground in the emerging markets. This study also corroborates Reinartz and Kumar’s (2002) marketing insight that to satisfy customers, make them loyal, is trivial for profitability and firm value in Korea perspective. The practical implication of our finding is that the relation between customer satisfaction and firm value becomes more ambiguous, especially when it is considered in the emerging market contexts. It also provides management with a fresh new insight that they should take prudence when they increase expenses on customer satisfaction since it turned out to be not a “panacea”

Optical and photoelectric properties of Mn-doped ZnS thin film on a flexible indium-tin-oxide/polyethylene terephthalate substrate prepared by pulsed laser deposition

Optical and photoelectric properties of Mn-doped ZnS thin films on indium-tin-oxide (ITO)/polyethylene terephthalate (PET) substrates by pulsed laser deposition (PLD) were investigated. The XRD patterns revealed that the thin film deposited at room temperature (RT) had a wurtzite phase, which changed to a sphalerite phase at a substrate temperature of approximately 100°C. The transmittance of the films was approximately 87% in the visible range. The optical bandgap of the film deposited at RT was 3.29 eV, which increased to 3.361 eV with increasing substrate temperature to 200°C. The photoluminescence (PL) intensity at 468 nm and the photocurrent by UV irradiation increased in proportion to the substrate temperature. The present results imply that Mn-doped ZnS films deposited on flexible PET substrates are useful for fabricating flexible optoelectronic devices such as flexible UV detectors. © 2016 Optical Society of America.1

Enhanced interlayer neutral excitons and trions in trilayer van der Waals heterostructures

Vertically stacked van der Waals heterostructures constitute a promising platform for providing tailored band alignment with enhanced excitonic systems. Here we report observations of neutral and charged interlayer excitons in trilayer WSe2-MoSe2-WSe2 van der Waals heterostructures and their dynamics. The addition of a WSe2 layer in the trilayer leads to significantly higher photoluminescence quantum yields and tunable spectral resonance compared to its bilayer heterostructures at cryogenic temperatures. The observed enhancement in the photoluminescence quantum yield is due to significantly larger electron-hole overlap and higher light absorbance in the trilayer heterostructure, supported via first-principle pseudopotential calculations based on spin-polarized density functional theory. We further uncover the temperature- and power-dependence, as well as time-resolved photoluminescence of the trilayer heterostructure interlayer neutral excitons and trions. Our study elucidates the prospects of manipulating light emission from interlayer excitons and designing atomic heterostructures from first-principles for optoelectronics.Comment: 25 pages, 5 figures(Maintext). 9 pages, 7 figures(Supplementary Information). - Accepted for publication in npg: 2D materials and applications and reformatted to its standard. - Updated co-authors and references. - Title and abstract are modified for clarity. - Errors have been corrected, npg: 2D materials and applications (2018

Diffusion-EDFs: Bi-equivariant Denoising Generative Modeling on SE(3) for Visual Robotic Manipulation

Diffusion generative modeling has become a promising approach for learning robotic manipulation tasks from stochastic human demonstrations. In this paper, we present Diffusion-EDFs, a novel SE(3)-equivariant diffusion-based approach for visual robotic manipulation tasks. We show that our proposed method achieves remarkable data efficiency, requiring only 5 to 10 human demonstrations for effective end-to-end training in less than an hour. Furthermore, our benchmark experiments demonstrate that our approach has superior generalizability and robustness compared to state-of-the-art methods. Lastly, we validate our methods with real hardware experiments. Project Website: https://sites.google.com/view/diffusion-edfs/homeComment: 31 pages, 13 figure

Bilateral Ageusia in a Patient with a Left Ventroposteromedial Thalamic Infarct: Cortical Localization of Taste Sensation by Statistical Parametric Mapping Analysis of PET Images

Unilateral taste loss is usually observed on the side contralateral to a thalamic infarction, despite gustatory function being represented bilaterally. We report a rare case of bilateral taste loss in a patient with an acute left unilateral thalamic infarction, with unilateral left insular hypometabolism demonstrated by statistical parametric map analysis of PET images. Our observations suggest that the left insular cortex and left ventroposteromedial thalamic nuclei are critical to bilateral gustatory sensation