Scientists Improve Behavior of Quantum Dots

Researchers from the University of Wisconsin-Madison recently revealed new effects in tiny electronic devices known as quantum dots. The potential for this research is huge, as it could very well pave the way for highly advanced computer systems. The findings of this research were recently published in the journal Nano Letters.

The researchers developed and applied analysis methods that they hope will aid in the development of electronic materials. “We can now look at a set of structures that people couldn’t look at before,” said University of Wisconsin-Madison Professor of Materials Science and Engineering Paul Evans. “In these structures, there are new sets of crucial materials problems that we previously weren’t able to think about solving.”

The structures are thousands of times more narrow than single sheets of paper and much smaller than the dimensions of individual human cells. Quantum dots within the structures form inside very thin stacks of crystalline materials topped by an asymmetrical arrangement of flat, metallic electrodes. Quantum dots are located between those metallic electrodes.

Creating these intricate structures and looking inside them and into the tiny spaces is challenging enough as it is, and it is even more difficult as quantum dots do not always behave as expected. Evans worked with a team of collaborators at the Delft University of Technology in the Netherlands. These collaborators had previously created and studied the crystal stack structures, which led to suspicions that the quantum dots were different in important ways from what had been designed. Until recently, measuring those differences was an impossible task.

“Previous imaging approaches and the modeling weren’t allowing people to structurally characterize quantum dot devices at this tiny scale,” said Anastasios Pateras, a postdoctoral scholar who authored the paper.

The researchers pioneered a strategy for using beams of very tightly focused X-rays to characterize the quantum dot devices, which allowed them to observe shifts in the spacing and orientation of atomic layers within the quantum dots. “Quantum dots need to be close to perfect,” said Evans. “This small deviation from perfection is important.”

The discovery indicates that the process of creating quantum dots distorts the material underneath, creating strain in the material and leading to small distortions in the dots themselves. Understanding this effect and effectively exploiting that fact could aid researchers in the improvement of quantum dot behavior. “Once you know these quantities,” said Evans, “then you can design devices that take into account that structure.”

“This is going to be very relevant because, right now, there are multiple sources of decoherence quantum dots,” said Pateras.

Going forward, the researchers are developing an algorithm to automatically visualize atomic positions in crystals from X-ray scattering patterns. They are also exploring how the techniques could provide insight into other structures that are difficult to study.

Did you miss this?

Other Popular Stories

  • GTA food and beverage manufacturers launch Cluster to spur growth
  • Car sales set records in November
  • Forestry industry pledges 13 per cent CO2 reduction to fight climate change
  • Solar-powered nanoheaters offer solution for off-grid medical sterilization
  • Canada's manufacturing sales rose in 2016, led by cars, food
  • Honda expansion a win for Ontario's auto sector
  • Global construction industry optimistic about future
  • Thunder Child, the unsinkable boat? Self-righting, wavepiercing interceptor engineered to be the perfect boat for offshore patrol
  • Researchers Create Negative Mass Superconductor
  • Grid-scale electricity storage solution from New York startup
  • Skills gap costing economy billions; Ontario students ill-prepared for workplace: report
  • SAFFir is an autonomous robot firefighter being tested by the Navy for dangerous situations. Unlike other firefighting robots, SAFFir is both autonomous, and stands on two legs, with two hands to grasp fire hoses.
    Robots save lives: robot fire-fighters take on explosive situations. SAFFiR shows how they can be ultimately be autonomous.
  • Goodbye NAFTA, Hello USMCA trade deal: it's not all in the name — Canadian dollar soars, stocks rise; autos win, dairy loses
  • CAE USA wins $200 million contract for Army training
  • Canadian manufacturing continued to slide in December, though not in Ontario
  • Transportation workers urge quick response to Lac-Megantic report
  • Federal government urged to speak up for nuclear at Paris climate talks
  • Study on the Effects of Space on Humans Has Interesting Results
  • 21 auto parts companies in Ontario invest in new technologies with help from Ontario Government
  • Bombardier upbeat about growth prospects now that CSeries jets are flying
Scroll to Top