Surface Reactions Following Ultra Fast Substrate Excitation: A Path Towards Atomic Scale Resolution of High-temperature Reactions at Metal Surfaces

2010 ◽  
Author(s):  
Ludwig Bartels
Keyword(s):  
High Temperature ◽  
Metal Surfaces ◽  
Surface Reactions ◽  
Atomic Scale ◽  
High Temperature Reactions

High-Temperature Synthesis of CdSe-Based Core/Shell, Core/Shell/Shell, and Core/Graded-Shell Nanoplatelets for Stable and Efficient Narrowband Emitters

2019 ◽  
Author(s):  
Aurelio A. Rossinelli ◽  
Henar Rojo ◽  
Aniket S. Mule ◽  
Marianne Aellen ◽  
Ario Cocina ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Temperature ◽  
Equilibrium Shape ◽  
Size Variation ◽  
Crystal Defects ◽  
Atomic Scale ◽  
Quantum Yields ◽  
Core Shell ◽  
Compositional Gradient ◽  
High Quality

<div>Colloidal semiconductor nanoplatelets exhibit exceptionally narrow photoluminescence spectra. This occurs because samples can be synthesized in which all nanoplatelets share the same atomic-scale thickness. As this dimension sets the emission wavelength, inhomogeneous linewidth broadening due to size variation, which is always present in samples of quasi-spherical nanocrystals (quantum dots), is essentially eliminated. Nanoplatelets thus offer improved, spectrally pure emitters for various applications. Unfortunately, due to their non-equilibrium shape, nanoplatelets also suffer from low photo-, chemical, and thermal stability, which limits their use. Moreover, their poor stability hampers the development of efficient synthesis protocols for adding high-quality protective inorganic shells, which are well known to improve the performance of quantum dots. <br></div><div>Herein, we report a general synthesis approach to highly emissive and stable core/shell nanoplatelets with various shell compositions, including CdSe/ZnS, CdSe/CdS/ZnS, CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S, and CdSe/ZnSe. Motivated by previous work on quantum dots, we find that slow, high-temperature growth of shells containing a compositional gradient reduces strain-induced crystal defects and minimizes the emission linewidth while maintaining good surface passivation and nanocrystal uniformity. Indeed, our best core/shell nanoplatelets (CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S) show photoluminescence quantum yields of 90% with linewidths as low as 56 meV (19.5 nm at 655 nm). To confirm the high quality of our different core/shell nanoplatelets for a specific application, we demonstrate their use as gain media in low-threshold ring lasers. More generally, the ability of our synthesis protocol to engineer high-quality shells can help further improve nanoplatelets for optoelectronic devices.</div>

Site-selective, resonant photochemical desorption of metal atoms with laser light: manipulation of metal surfaces on the atomic scale

2003 ◽  
Vol 526 (1-2) ◽  
pp. L151-L157 ◽  
Author(s):  
D. Martin ◽  
T. Jacob ◽  
F. Stietz ◽  
B. Fricke ◽  
F. Träger
Keyword(s):  
Metal Surfaces ◽  
Laser Light ◽  
Atomic Scale ◽  
Light Manipulation ◽  
Metal Atoms ◽  
Site Selective

scholarly journals Microstructural characterization of alkali metal mediated high temperature reactions in mullite based refractories

2010 ◽  
Vol 36 (2) ◽  
pp. 733-740 ◽  
Author(s):  
J. Stjernberg ◽  
B. Lindblom ◽  
J. Wikström ◽  
M.-L. Antti ◽  
M. Odén
Keyword(s):  
High Temperature ◽  
Alkali Metal ◽  
Microstructural Characterization ◽  
High Temperature Reactions

High-temperature reactions and orientation of YBa2Cu3O7−δ

1992 ◽  
Author(s):  
B. J. Chen ◽  
M. A. Rodriguez ◽  
S. T. Misture ◽  
R. L. Snyder
Keyword(s):  
High Temperature ◽  
High Temperature Reactions
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