İki boyutlu fotonik kristal yapıları gömülü IngaN/GaN çoklu kuantum kuyulu ışık saçan diyotların ışık çıkarım verimlerini artırma

Potential performance of III-Nitride based devices is hindered mainly because of an optical phenomenon called total internal reflection (TIR). With a refractive index of 2.7, GaN material has 22°-24° critical angle which means less than 12% of light can just escape the structure. While 66% of the light generated in quantum well region of a GaN based light emitting diode (LED) is trapped in the GaN layer, 22% of the light is guided in the sapphire substrate. In order to increase the extraction efficiency of GaN based LEDs, two dimensional photonic crystals were used in this thesis. LED wafers used were fabricated in collaboration with University of Santa Barbara, California (UCSB). These LED wafers were processed in the scope of the thesis and photonic crystal (PC) structures were patterned on the p layer of the device.This thesis work is concentrated on two parts; first part is characterization and fabrication, and second part is simulation. In characterization and fabrication part, firstly GaN material etching characterizations were completed using dry etching method by reactive ion etcher (RIE). After characterization step was completed, p doping activation was done and then LED wafers were processed in clean room class-100 environment, As a final step, two dimensional square and triangular photonic crystal lattice structures were patterned by using electron beam writer and these structures were transferred on to p layer of GaN LED by using RIE. Measurements and imaging regarding material and optical properties, fabrication quality and extraction enhancement.