Study of Optoelectronic Properties of Nano Structure InGaN/GaN Light Emitting Diodes

In the advance of nano technologies, many novel LED structures such as nanocolumn, nanorod, and photonic devices have been proposed to show better device performance. In order to analyze these structures, we have applied the valence force field model and self-consistent Poisson, drift-diffusion, and Schrodinger to analyze the InGaN/GaN quantum well LEDs with different nano structures. We first describe the correlation between the energy blue shifts and the strain relaxation of multiple quantum wells embedded in nanorods with different averaged sizes. We also studied the emission properties of InGaN/GaN quantum well light emitting diodes when the etching depths of nanohole arrays are close to or penetrate the quantum well structures. The effects of strain relaxation and surface states are analyzed, which could possibly influence the diode emission properties. Our results suggest that the effects of strain relaxation and sizes of nano structure dimensions strongly influence the emission properties of the nanorod LEDs. In this thesis, we will discuss these information in great detail. The roles of strain relaxation, piezoelectric effect, surface states, and non-radiative recombination mechanism will all be included in this thesis. Our calculation results can provide useful information in analyzing emission properties of these imilar nano structure LEDs.