%0 Journal Article
%T Effect of Die Shape and Size on Performance of III-Nitride Micro-LEDs: A Modeling Study
%A Kirill A. Bulashevich
%A Sergey S. Konoplev
%A Sergey Yu. Karpov
%J Photonics | An Open Access Journal from MDPI
%D 2018
%R https://doi.org/10.3390/photonics5040041
%X Abstract Flip-chip truncated-pyramid-shaped blue micro-light-emitting diodes (¦Ì-LEDs), with different inclinations of the mesa facets to the epitaxial layer plane, are studied by simulations, implementing experimental information on temperature-dependent parameters and characteristics of large-size devices. Strong non-monotonous dependence of light extraction efficiency (LEE) on the inclination angle is revealed, affecting, remarkably, the overall emission efficiency. Without texturing of emitting surfaces, LEE to air up to 54.4% is predicted for optimized shape of the ¦Ì-LED dice, which is higher than that of conventional large-size LEDs. The major factors limiting the ¦Ì-LED performance are identified, among which, the most critical are the optical losses originated from incomplete light reflection from metallic electrodes and the high p-contact resistance caused by its small area. Optimization of the p-electrode dimensions enables further improvement of high-current wall-plug efficiency of the devices. The roles of surface recombination, device self-heating, current crowding, and efficiency droop at high current densities, in limitation of the ¦Ì-LED efficiency, are assessed. A novel approach implementing the characterization data of large-size LED as the input information for simulations is tested successfully. View Full-Tex
%K micro-LEDs
%K InGaN
%K light extraction efficiency
%K external quantum efficiency
%K surface recombination
%K current crowding
%K self-heating
%K simulation
%K optical losses
%U https://www.mdpi.com/2304-6732/5/4/41