Cathodoluminescence on GaN hexagonal pyramids on submicron dot-patterns via selective MOVPE

Three-dimensional GaN pyramids have been successfully obtained on submicron dot-patterned 0001.sapphire substrates by using the selective metalorganic vapor phase epitaxy MOVPE.technique. The dot-pattern is a hexagon arranged with a 0.5-mm width and 1.0-mm spacing. The GaN structure comprises a hexagonal pyramid covered with six 11014pyramidal facets on the side of a hexagonal pyramid having a 0001.facet on the top. Cathodoluminescence CL.measurement was carried out on the hexagonal pyramid at low temperature. Two distinct spectra were observed to occur at about 359 and 329 nm. The higher energy is thought to be related to GaN dot, and the lower one is due to GaN dot band edge emission. The intensities of the two spectra were investigated as a function of temperature in the range of 135–150 K. q2000 Published by Elsevier Science B.V.