Epitaxial growth of one-dimensional GaN nanostructures with enhanced near-band edge emission by chemical vapor deposition

We report a simple chemical vapor deposition method for epitaxial growth of hierarchical GaN one-dimensional nanostructures (1DNSs) that have good optical characteristics. By changing the evaporation temperature of the Ga source, we were able to change the morphologies of GaN 1DNSs from hexagonal-faceted, pencil-like structures to rough-surfaced, polygonal towerlike structures. Furthermore, we investigated the correlation between the morphology and the luminescence characteristics of the GaN 1DNSs. Spatially and spectrally resolved cathodoluminescence (CL) measurements revealed that the relative near-band edge emission intensities of the GaN 1DNSs were 8-20 times higher than that of GaN thin film. In addition, pencil-like GaN 1DNSs exhibited 2.5-fold greater CL intensity than polygonal towerlike 1DNSs. These results indicate that controlling the surface morphology of GaN 1DNSs allows improvement in the optical properties of GaN nanostructures.This work was financially supported by National Research Foundation of Korea (NRF) through Grant No. (K20704000003TA050000310, Global Research Laboratory (GRL) Program) provided by the Korean Ministry of Education, Science and Technology (MEST) in 2009