Effect of strain on aluminum nitride/gallium nitride Distributed Bragg Reflectors

III - N Distributed Bragg Reflectors (DBRs) are important components to nitride based optoelectronic devices. Nitride based DBRs are critical to the operation and performance of both Vertical Cavity Surface Emitting Lasers (VCSELs) and Light Emitting Diodes (LEDs). Aluminum Nitride (AlN)/Gallium Nitride DBRs are of particular interest because their high refractive index contrast allows the fabrication of DBRs with high reflectivity using a relatively low number of periods.;The growth of high quality AlN/GaN DBRs has been held back because of tensile strain resulting from the 2.4% lattice mismatch between AlN and GaN. This tensile strain has led to cracking in DBRs and has significantly decreased their overall reflectivity. Reducing this strain and subsequent cracking is critical to improving AlN/GaN DBR reflectivity and the overall efficiency of nitride based optoelectronic devices.;This work will focus on the characterization, simulation, and development of AlN/GaN DBRs. Individual AlN and GaN thin films will be characterized to determine their properties and promise for development DBR structures. AlN/GaN DBR structures will then be characterized and simulated to determine their overall performance. Finally, the effect of strain on both the apparent refractive index of individual layers and the overall performance of AlN/GaN DBRs will be investigated.