Phosphine-free engineering toward the synthesis of metal telluride nanocrystals: the role of a Te precursor coordinated at room temperature

Nanoscale ◽  
2018 ◽  
Vol 10 (46) ◽  
pp. 21928-21935 ◽  
Author(s):  
Min Wu ◽  
Yixuan Wang ◽  
Hongyu Wang ◽  
Hao Wang ◽  
Yongming Sui ◽  
...  
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
High Quality ◽  
Application Prospects ◽  
Quality Metal

We developed a new phosphine-free strategy for fabricating high-quality metal telluride nanocrystals (NCs) by using a highly reactive Te precursor coordinated at room temperature. These metal telluride NCs with good optical properties possess excellent application prospects.

Role of non-magnetic dopants on the room temperature ferromagnetism and optical properties of BaSnO3 perovskite

2020 ◽  
Vol 281 ◽  
pp. 121028 ◽  
Author(s):  
Saad Mabrouk Yakout ◽  
Hanan A. Mousa ◽  
Hala T. Handal ◽  
Walid Sharmoukh
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism

Crucial role of reactive pulse-gas on a sputtered Zn3N2 thin film formation

RSC Advances ◽  
2016 ◽  
Vol 6 (97) ◽  
pp. 94905-94910 ◽  
Author(s):  
Narathon Khemasiri ◽  
Chanunthorn Chananonnawathorn ◽  
Annop Klamchuen ◽  
Sukittaya Jessadaluk ◽  
Apirak Pankiew ◽  
...  
Keyword(s):  
Room Temperature ◽  
Film Formation ◽  
Rf Magnetron Sputtering ◽  
Energy Sources ◽  
High Quality ◽  
Additional Energy ◽  
Thin Film Formation ◽  
Reactive Pulse ◽  
Reactive Gas

Herein, we demonstrate a powerful technique, known as reactive gas-timing (RGT) rf magnetron sputtering, to fabricate high quality Zn3N2 thin films at room temperature without applying any additional energy sources.

scholarly journals Novel approaches for robust polaritonics

2015 ◽  
Author(s):  
Rahul Jayaprakash
Keyword(s):  
Optical Properties ◽  
Active Region ◽  
Room Temperature ◽  
Sacrificial Layer ◽  
Bragg Reflector ◽  
Oscillator Strengths ◽  
Strong Coupling Regime ◽  
High Quality ◽  
Gan Nanowires ◽  
Low Threshold

The possibility of having low-threshold, inversion-less lasers, makinguse of the macroscopic occupation, of the low density of states, at thebottom of the lower polariton branch, has intensified polariton researchin the last two decades. State of the art devices based on this admixedquasiparticle have already been realized using GaAs and CdTe active layers,although the accomplishment of room temperature lasers has beenlimited by their relatively weak exciton binding energy. The high excitonbinding energy and oscillator strength, as well as the advantageous relaxationdynamics of wide bandgap semiconductors, such as GaN, are wellsuited for room temperature polariton operation. The up to date demonstrationsof GaN based polariton lasers have used as the active layer bulkGaN, GaN quantum wells (QW’s), and GaN nanowires. In the latterapproach, individual nanowires are positioned in a microcavity showingremarkable polariton characteristics, but questions remain on the scalabilityof the approach, as well as on how to turn these nanowire-basedstructures into real electrically-injected devices. The former two casesare technologically viable, but are currently limited by the relatively poorquality of the active region, due to the structural disorder introduced bythe bottom GaN based Distributed Bragg Reflector (DBR) mirrors.In this thesis, a very straightforward processing technique is used toetch away an InGaN sacrificial layer, using photo-electrochemical (PEC)etching, creating ultra-smooth membranes containing GaN/AlGaN QW’s,which are then embedded between high quality dielectric DBR mirrors,on which polaritonic studies are performed. The GaN membrane or the active region is carefully engineered, ensuring superior optical properties,both prior to and after etching. At room temperature, the QW emission isstate of the art, with a linewidth of ~ 28meV, and a corresponding lifetimeof ~ 275ps. The PEC lateral etching parameters are optimised in sucha way, that the rms roughness of the membranes, measured by AtomicForce Microscopy (AFM), is as small as 0.65nm, very close to epitaxialquality. A temperature dependent study on the full-microcavity structure,unveils the strong coupling regime, exhibiting a robust Rabi splittingas large as 64meV at room temperature. The non-linear propertiesare examined, under non-resonant quasi-continuous excitation, with polaritonlasing demonstrated at an ultra-low, average threshold of ~ 4.5W/ cm2(~ 594μJ / cm2), the lowest ever reported for a 2D GaN basedsystem, accompanied by a spectacular condensation pattern in k-space.The latter is attributed to a site-specific polariton trapping mechanism,where polaritons accumulate in discrete levels within the trapping potential,helping to escalate the polariton density locally. This, along with thehigh optical quality of the all-dielectric microcavity (Q-factor ~ 1770), explainsthe obtained ultra-low threshold. It should be noted that the useof ultra-smooth GaN membranes in microcavities is fully compatible withthe realisation of electrically injected GaN polariton devices.In the direction of obtaining even more robust polaritonic devices, thebasic optical properties of high quality, strain free, GaN nanowires arestudied. However, to make the most out of this novel system, the absorptioncoefficients are extracted from as-grown GaN nanowires, on silicon<111>substrates, developing an all-optical method, analysing merelythe reflectivity spectra, which is demonstrated for the first time. It shouldbe noted that the absorption coefficients (directly proportional to oscillator strengths) corresponding to the excitons, provide a glance into theappropriateness of the respective GaN nanowire system, as optimal candidatesfor hefty polaritonics. However, the nanowires studied here, failedto shown an enhancement of absorption, which can be mainly attributedto the nanowire dimensions. The new method demonstrated here, can beextended to any family of nanowires, provided they are grown on a substratehaving considerable difference in permittivity with the nanowire-airmatrix.

Low Temperature Processing for Multilevel Interconnection and Packaging

1990 ◽  
Vol 181 ◽  
Author(s):  
T.-M. Lu ◽  
J. F. McDonald ◽  
S. Dabral ◽  
G.-R. Yang ◽  
L. You ◽  
...  
Keyword(s):  
Room Temperature ◽  
Metal Films ◽  
High Density ◽  
Deposition Technique ◽  
High Quality ◽  
Low Temperature Processing ◽  
Substrate Temperatures ◽  
And Diffusion ◽  
Quality Metal ◽  
Beam Deposition

ABSTRACTThe future high density multilevel interconnection and packaging requires that the combination of the insulator and conductor layers has a low RC value. Thermal stress and diffusion during processing are issues of great concern in the high density multilevel structures. The problem can be alleviated by a proper choice of materials and processes that do not require high temperature. In this paper we propose to use parylene and its derivatives (dielectric constant 2.3–2.6) as the possible interlayer dielectrics and Cu (bulk resistivity ∼1.7 μ Ω-cm) as the conductor. Parylene can be vapor-deposited and cured at room temperature. The metallization of Cu has been achieved at room temperature using the newly developed partially ionized beam deposition technique. This technique has been shown to grow high quality metal films with low resistivity at low substrate temperatures. The interaction between Cu and parylene, including adhesion and diffusion, is also discussed.

Making Movies and Community of Talent

2019 ◽  
Vol 10 (11) ◽  
pp. 1057-1064
Author(s):  
Katsuhiko Hirasawa ◽  
Keyword(s):  
Shop Floor ◽  
High Quality ◽  
Democratic Leadership ◽  
Staff Members

Staff members at a movie company Daiei, known for presumably the world’s best film technology, continued to produce movies for several months even after the company went bankrupt. It was because they desired to make outstanding films. A director can create a high-quality film by combining the skills and ideas of such staff. Akira Kurosawa named the group that could produce excellent works the “Community of Talents”. By using research on a community as a clue, this paper aims to highlight how the “Community of Talents” is organized. First I point out that a “Community of Talents” is formulated primarily by the labor of the staff based on Kumazawa’s “Community on the Shop Floor”. The paper subsequently refers to research by Heinrich Nicklish, a representative researcher on the study of community in Germany, in an attempt to verify that the community is a group of people established on functions. Lastly, the paper explores Guido Fisher’s research to reveal the role of democratic leadership centered on the director who transforms the objectified staff in the organization into an independently-minded presence and help them prove their abilities. The paper continues to emphasize the significance of leadership in the formation of the “Community of Talents”.

Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Spin Orbit Coupling ◽  
Design Rationale ◽  
Emission Mechanism ◽  
Room Temperature Phosphorescence ◽  
Electronic Interactions ◽  
Energy Gaps ◽  
Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

THEORETICAL GROUNDS FOR FORMATION OF HIGH QUALITY METAL-CERAMIC COATINGS BY CARBOVIBRATING ELECTRODE ARC STRENGTHENING

2020 ◽  
pp. 2-11
Author(s):  
N. V. TITOV ◽  
◽  
A. V. KOLOMEYCHENKO ◽  
V. L. BASINYUK ◽  
I. N. KRAVCHENKO ◽  
...  
Keyword(s):  
Ceramic Coatings ◽  
High Quality ◽  
Metal Ceramic ◽  
Quality Metal

Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Ros ◽  
C. Canals-Batlle ◽  
M.A. Lillo-Ródenas ◽  
E. Fuente ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Room Temperature ◽  
Waste Water Treatment ◽  
Textural Properties ◽  
Active Species ◽  
Elemental Sulphur ◽  
Gaseous Emissions ◽  
Removal Experiments ◽  
Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

When Do Auditors Use Specialists' Work to Improve Problem Representations of and Judgments about Complex Estimates?

2017 ◽  
Vol 93 (4) ◽  
pp. 177-202 ◽  
Author(s):  
Emily E. Griffith
Keyword(s):  
Pattern Recognition ◽  
Situational Factors ◽  
Situational Factor ◽  
High Quality ◽  
Quality Audit ◽  
Domain Specific ◽  
Epistemic Motivation ◽  
Specific Expertise ◽  
Problem Representations

ABSTRACT Auditors are more likely to identify misstatements in complex estimates if they recognize problematic patterns among an estimate's underlying assumptions. Rich problem representations aid pattern recognition, but auditors likely have difficulty developing them given auditors' limited domain-specific expertise in this area. In two experiments, I predict and find that a relational cue in a specialist's work highlighting aggressive assumptions improves auditors' problem representations and subsequent judgments about estimates. However, this improvement only occurs when a situational factor (e.g., risk) increases auditors' epistemic motivation to incorporate the cue into their problem representations. These results suggest that auditors do not always respond to cues in specialists' work. More generally, this study highlights the role of situational factors in increasing auditors' epistemic motivation to develop rich problem representations, which contribute to high-quality audit judgments in this and other domains where pattern recognition is important.

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