Morphological, optical, and photoluminescent characteristics of GaAs1-xNx nanowhiskered thin films

GaAs1-xNx solid-solution thin films of nanometric size were prepared on gla ss substrates by the radio-frequency sputtering technique. Atomic-force mic roscopy images show that the films are composed of grains with a whisker sh ape, whose size is practically independent of the substrate temperature. Th eir typical diameters range between 40 and 45 Angstrom. The surface morphol ogy exhibits a high density of whisker-like features that are almost normal to the substrate plane. This density increases as the substrate temperatur e increases, but, in essence, the nanowhisker diameter does not. Optical ab sorption spectra of the samples show a band-gap energy blueshift as large a s 1.5 eV with respect to that of the GaAs bulk value, which was associated with strong quantum-confinement effects. Photoluminescence emission spectra in the blue range of 428-438 nm confirm the quantum-size effects in the Ga As1-xNx nanowhiskered thin films. (C) 2001 American Institute of Physics.