NANOSTRUCTURED GAN - MICROSTRUCTURE AND OPTICAL-PROPERTIES

In the present study, the microstructure and optical properties of a n anostructured composite that consists of nanocrystalline GaN imbedded in a poly(methyl methacrylate) thin film matrix (GaN/PMMA) are reporte d. X-ray powder diffraction and high-resolution transmission electron microscopy were performed to analyze the microstructure, while the opt ical properties were measured by optical absorption and photoluminesce nce. Microstructural analyses showed that GaN nanocrystallites imbedde d in the PMMA matrix have a size of about 5.5 nm, and crystallize in t he zinc-blende lattice (the lattice constant a(0) similar to 0.45 nm) with a considerable fraction of structural defects such as nitrogen; v acancies and stacking faults. Optical-absorption measurements indicate that the band-gap energy of the GaN/PMMA composite is approximately 3 .51 eV.