Researchers at University College London, the University of Bath and Daresbury Laboratory, Cheshire, UK, have used computer simulations to help explain why making blue light-emitting diodes (LEDs) using gallium nitride is so difficult. Blue LEDs have been available commercially for twenty years and are used in energy-saving lighting and many other applications. They earned their inventors the 2014 Nobel Prize in Physics. However, there has been a gap in our knowledge as to how gallium nitride actually works to produce light of the required wavelength; it needs a lot of magnesium dopant. Now, UCL chemist John Buckeridge and colleagues have simulated the doping of this material and demonstrated that when you add a magnesium atom, it replaces a gallium atom but does not donate the positive charge to the material. The discovery could help scientists develop an alternative doping strategy for making new types of blue LED.
The LED blues