The linked article has little details and 30 seconds of searching on the Uni website didn't turn up more specifics BUT...
a lot of the light produced inside an LED is unable to escape from the semiconductor (ie the material that produces the light) because it gets internally reflected (imagine the light is generated inside a box, and the inside of the walls are mirrors - the idea is to make the mirrors more like windows in order to let the light out of the box).
Roughening of the surface (easiest idea to imagine) can help to reduce the reflectivity of the side walls of the LED. This enables more photons (light particles) to escape - and in fact would REDUCE the temperature of the device as these photons do not get stuck inside and turn into heat.
It sounds as though they are simply increasing extraction efficiency, but it is unclear if it is a photonic crystal type approach (basically making a pattern of holes to choose wavelengths of light to transmit - like the pattern of holes on your microwave door that stop that wavelength of radiation from escaping through the glass door).
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The linked article has little details and 30 seconds of searching on the Uni website didn't turn up more specifics BUT...
a lot of the light produced inside an LED is unable to escape from the semiconductor (ie the material that produces the light) because it gets internally reflected (imagine the light is generated inside a box, and the inside of the walls are mirrors - the idea is to make the mirrors more like windows in order to let the light out of the box).
Roughening of the surface (easiest idea to imagine) can help to reduce the reflectivity of the side walls of the LED. This enables more photons (light particles) to escape - and in fact would REDUCE the temperature of the device as these photons do not get stuck inside and turn into heat.
It sounds as though they are simply increasing extraction efficiency, but it is unclear if it is a photonic crystal type approach (basically making a pattern of holes to choose wavelengths of light to transmit - like the pattern of holes on your microwave door that stop that wavelength of radiation from escaping through the glass door).