Ismail ALTUNTAS
Cumhuriyet University, Turkey
Title: Compherensive comparison of epitaxially grown gan layer grown on conventional sapphire and patterned sapphire substrates
Biography
Biography: Ismail ALTUNTAS
Abstract
GaN based materials including light emitting diodes, blue laser diodes and high-power microwave transistors have received much attention over the past few years. An important problem of these structures is the high levels of structural defects, mostly dislocations, due to the lack of a suitable lattice-matched substrate So far, the substrate of choice has been mainly sapphire (Al2O3) substrates, which has a large lattice mismatch with GaN or AlN. As a result, (0001) GaN layers epitaxially grown on sapphire subtrates include high concentrations of misfit and threading dislocations. In this study, epitaxial GaN layers have been grown on both conventional sapphire and patterned sapphire substrates by using an MOCVD system and high resolution XRD scans and photoluminescence measurements are performed to compare the effect of patterned sapphire substrates on the dislocation density.