Morphology and composition of GaN films grown by cyclic-pulsed laser deposition

We describe a detailed study of scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS) analysis to study composition and structure of 500 nm thick polycrystalline GaN samples. The films have been deposited by cyclic-pulsed laser deposition (cyclic-PLD) with a Nd:YAG nanosecond pulsed laser at 1064 nm. SEM pictures of the GaN layers revealed a structure composed of grains with typical dimensions of 200 nm. Coalescence of the grains was more evident for a 1 μm thick sample. EDS mapping of the GaN layer was performed for Ga, N, O, and Al and could be related with the corresponding SEM scan. Both EDS and XPS composition analyses pointed to a Ga rich (or N deficient) GaN layer.