A method that can be used to predict the growth of earthquake faults also aids prediction of the tiniest of phenomena--how arrays of "artificial atoms," or quantum dots, assemble and stack themselves on semiconductor materials, National Institute of Standards and Technology (NIST) researchers report in the July 15 issue of Physical Review B.
The insight could aid development of more reliable methods for fabricating lasers, sensors and other devices that exploit quantum dots special electronic properties -- the result of confining electrons in the space of a few nanometers. The minuscule structures already are the basis for some lasers. Yet, difficulties in making quantum dots of uniform size and precisely positioning them on a substrate remain formidable. These obstacles stand in the way of an array of faster, more powerful electronic and photonic devices that require only small inputs of energy to spring into action.
NISTs Bo Yang and Vinod Tewary borrowed a mathematical concept that explains how cracks grow in a solid, such as the Earths crust or an airplane wing. The concept, called the elastic energy release rate, accounts for how energy is apportioned as a crack advances. The scientists found that the rate also accounts for how self-assembling quantum dots, which strain the systems lattice-like atomic geometry, will position and align themselves among their neighbors--those next door and those living below. For cube-shaped quantum dots, at least, the equation predicts the most "energetically favorable" location for a quantum dot. The NIST pair says their theory can be used, for example, to predict the optimal depth for embedding quantum dots that will be overlain by another array of dots.
Mark Bello | EurekAlert!
UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire
NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
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16.11.2018 | Life Sciences
16.11.2018 | Life Sciences