Hydrostatic Pressure Spectroscopy of the Vanadium Luminescence in GaAs

We report luminescence measurements of the intracenter transition $\text{}^{3}$T$\text{}_{2}$ → $\text{}^{3}$A$\text{}_{2}$ of the V$\text{}^{3+}$(3d$\text{}^{2}$) charge state in semi-insulating GaAs under hydrostatic pressure up to 0.8 GPa at liquid helium temperature. The hydrostatic pressure coefficient of the zero-phonon line is found to be equal to 6.9 ± 0.2 meV/GPa. This result enables us to determine the Huang-Rhys parameter, which characterizes the coupling to the symmetric mode of vibration, as S$\text{}_{A}$ = 1.4 ± 0.1. Using this parameter, computer simulation leading to a reconstruction of the shape of both luminescence and corresponding absorption spectra were performed.