Thermally induced amorphous to crystalline transformation of argon ion bombarded GaAs studied with surface Brillouin and Raman scattering

Surface Brillouin scattering (SBS) and Raman spectroscopy have been used to investigate the recrystallisation of an amorphous layer of GaAs created on single crystal (0 0 1) GaAs by ion bombardment with 100 keV argon ions with a fluence of 5 × 1016 ions/cm2 at a temperature of ∼65 °C. Samples were isochronally annealed and the light scattering measurements were performed after each annealing step. The SBS studies confirm structural changes resulting in continuous stiffening of the layer beginning above 200 °C and finally attaining a maximum value above 500 °C. The Raman studies show evidence of full recrystallisation above 500 °C, with the appearance of both LO and TO peaks indicating that the reformed layer is polycrystalline.