Annealing of deep level defects in GaAs nanostructures by ion beam irradiation

Abstract

Present study reports the fabrication of Gallium Arsenide (GaAs) nanostructures on silicon (Si) substrates with the help of GaAs ions produced by hot and dense argon plasma in a modified dense plasma focus device. The fabricated nanostructures are further irradiated by Ar2+ ion beam having energy of 100 keV and fluences of 1 × 1013 ions/cm2, 5 × 1014 ions/cm2 and 5 × 1015 ions/cm2 in a ion beam accelerator. The morphological, stoichiometric and optical properties of as-fabricated and ion beam irradiated nanostructures have been compared to study the presence of defect states. As-deposited GaAs nanodots were found to be modified as nanostructured films upon ion irradiation. Excess arsenic present in as-deposited nanodots as deep level defect, is removed from ion irradiated nanostructured films. Thus, we found that the deep level defect states i.e., arsenic antisite (EL2) were annealed out in ion irradiated samples as is evident from Raman and photoluminescence spectra. It is found that ion irradiation reduces the EL2 defects in nanostructured films which have immense potential applications in enhancing efficiency of optoelectronic and electronic devices.