A new structure of nitride light-emitting diodes without polarization effects

In conventional nitride light-emitting diodes (LEDs) manufactured on the standard polar substrates, polarization effects hamper in reaching efficient sources of green radiation. Those effects may be completely avoided in non-polar crystallographic orientations, but then there are problems with reaching relatively high indium contents necessary for the green emission. Hence a possibility of an application of the semi-polar orientations should be considered. As a promising example, we have decided to consider possible compositions of the InxAlyGa1−x−yN barrier material adjusted with its polarization to the In0.3Ga0.7N quantum-well (QW) layer, expected to be the best suited for an emission of the green radiation. It is shown in the paper with the aid of the comprehensive mechanical and piezoelectric LED simulations, that, for the semi-polar (112¯2) crystallographic orientation (inclination angle of 58°), an application of the In0.19Al0.20Ga0.61N barriers for the In0.3Ga0.7N QWs leads to a complete elimination of unwanted polarization effects in the nitride LEDs emitting the green radiation.