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Cambridge Centre for Gallium Nitride


Current white light bulbs based on GaN use blue LEDs, and other colors of light within the visible spectrum are then produced by downconversion of light by a phosphor material. The use of phosphors inherently reduces the efficiency of green LEDs whilst simultaneously increasing their cost. If efficient green LEDs were available, white light could be generated by combining emission from efficient red, green and blue LEDs, eliminating downconversion losses and rending LED light bulbs tunability by altering the balance of red, green and blue light emitted by the separate devices.

The aim of my PhD project is to understand the factors limiting the efficiency of green LEDs and to develop methods mitigating them. Longer emission wavelengths require higher indium contents, and to achieve this growth is usually carried out at lower temperatures. However, this low temperature growth is thought to increase the incorporation of point defects which make the LED less efficient. In order to grow the LED at a higher temperature, while still maintaining a sufficient indium content for green emission, various growth strategies can be explored. I will participate in the design of experimental campaigns for the growth of green LED structures and research the impact of growth conditions on their properties.

Mr Boning  Ding