Multiscale modeling of wurtzite InN/GaN quantum Dot LEDs

The objective of this paper is to study the (competing) effects of various internal (built-in) fields on the electronic structure and optical properties of wurtzite InN/GaN quantum dot light emitting diodes (LEDs). A multiscale approach has been employed where: 1) the atomistic NEMO 3-D tool is used to calculate the strain distribution and one-particle electronic states, and 2) using the NEMO 3-D outputs, the Synopsys TCAD tool is then used to determine the terminal electrical and optical properties of the device. A list of the main findings is as follows: 1) Internal fields are long-ranged and their proper treatment demands simulation of realistically extended structures with millions of atoms; 2) Electronic structures show unconventional characteristics related to level shifts, non-degeneracy in the excited P states, and rotation (symmetry breaking) of the wavefunctions; and 3) Internal fields in these nanostructured LEDs lead to strong suppression in the interband optical transitions (near the center of the Brillouin zone) and the conversion efficiency.