Room-temperature exciton luminescence from GaN films fabricated by microwave-excited N Plasma epitaxial growth

Gallium Nitride (GaN) films with a hexagonal structure were grown on aluminum nitride (AIN) substrates in gallium and nitrogen plasma exited by microwave power. The photoluminescence properties of the GaN films were studied at various temperatures as well as various excitation densities. A strong ultraviolet emission, which consisted of two components, was observed even at room temperature. On the basis of the spectral position as well as its temporal behavior, the origin of the two components was attributed to the radiative recombination of free and localized excitons.