Nanostructured GaAs(N) thin films prepared by RF sputtering

An rf sputtering system with a GaAs target was used to grow GaAs(N) nanostr uctured thin films, on 7059 Coming glass substrates in a N-2 ambient at 10 mTorr, during 120 min. Different substrate temperatures (T-s) were used in the range from room temperature to 400 degrees C. By Auger spectroscopy it was only possible to determine that the nitrogen content is about 1 at.%. A tomic force microscopy allowed to resolve a well defined fibrous-nature of films, i.e., the grains have the aspect of whiskers. X-ray diffraction patt erns were employed to calculate the average grain size of whiskers that was in the range 4.0 to 5.5 nm. The average grain size of whiskers does not ch ange by increasing T-s, however, the density of whiskers increases with T-s following the relationship exp[-a(T/T-m)], where T-m is the melting point of GaAs and a is a fitting parameter. The growth process is in agreement wi th the predictions reported by other authors.