Thermal annealing effects on the optical and structural properties of (100) GaAs_(1-x)Bi_x layers grown by Molecular Beam Epitaxy

摘要

The effects of long time thermal annealing at 200 ℃ on the optical and structural properties of GaAs_(1-x)Bi_x alloys were investigated by X-ray diffraction (XRD), field emission scanning electron micros­copy (FESEM), high resolution transmission electron microscopy (HRTEM) and photoluminescence (PL). FESEM images show that bismuth islands nucleate on the surface and their diameter increases after annealing. It was observed a PL intensity enhance­ment and a small blue shift in PL peak energy after thermal anneal­ing at 200 ℃ for 3 h of GaAs_(1-x)Bi_x alloys which was associated to the reduction of the density of defects. However these defects are not completed removed by thermal annealing although an impor­tant PL intensity improvement is observed.