Photoluminescence and Raman Studies on $\mathrm{GaAs}_{1-\mathrm{x}}\mathrm{Bi}_{\mathrm{X}}$ Grown on GaAs

Photoluminescence (PL) and Raman studies were carried out to investigate the effect of growth rate on $\mathrm{GaAs}_{1-\mathrm{x}}\mathrm{sBi}_{\mathrm{x}}$ alloys. The samples were grown between 0.09 and 0.5 $\mu\mathrm{m}/\mathrm{hour}$, At room temperature, the lowest PL peak energy (1.07 eV) was obtained by sample grown at 0.23 $\mu\mathrm{m}/\mathrm{hour}$. Samples grown at lower and higher than 0.23 $\mu\mathrm{m}/\mathrm{hour}$ showed PL peak energy redshift and blueshift, respectively. Raman data show peaks at 162, 228, 270 and 295 cm−1which correspond to the GaAs like phonons. The GaBi like phonons were also observed at 183 and 213 cm−1but their intensity are significantly weaker compared to GaAs like phonons. PL and Raman data show that Bi incorporation into GaAs lattice is dependent on the growth rate and in this study, the highest Bi concentration was obtained for sample grown at 0.23 $\mu \mathrm{m}/\mathrm{hour}$.