The ZeroR project aimed to explore and identify the possibilities offered by eliminating Joule heating and contact shadowing in high power LEDs and solar cells by using the principle of diffusion driven charge transport. This involved studying the optimal device structures, their experimental realization and most attractive commercialization pathways. For the device structures it was concluded that the studied devices could clearly outperform conventional devices due to several benefits obtained by the structure, most notable being the possibility to eliminate contact shadowing, and to nearly eliminate current crowding and Joule heating effects. For smaller operating powers higher efficiencies were also predicted due to the suppression of surface recombination. For the experimental device demonstrations, the project explored both selective area growth of GaN devices as well as diffusion doping on GaAs based devices, providing first prototype devices revealing selected further optimization targets for the fabrication process.
The commercialization study focused on the lighting applications and suggested that the benefits could be valuable in several different fields ranging from portable event lighting to street and greenhouse lighting. The added value of the approach would be obtainable through collaboration with the LED chip manufacturers but this was also predicted to be challenging due to the highly concentrated markets and the still presently incomplete experimental demonstrations.
