The LED blues

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.