Figure 1

PL spectra of the conduction band to heavy-hole transition, for varying lattice temperature.Reuse & Permissions

Figure 2

Comparison of (a) the PL peak energy (1.379 eV) with (b) the heavy-hole to conduction band energy measured by contactless ER for a 1.36% ${\mathrm{GaAs}}_{1-x}{\mathrm{Bi}}_x$ sample at 150 K. The fit curve is composed of two third-derivative functions appropriate for an $M_0$ critical point in a three-dimensional system, under the low-field limit.Reuse & Permissions

Figure 3

PL spectra at the SO transition energy for 1.4% ${\mathrm{GaAs}}_{1-x}{\mathrm{Bi}}_x$ and varying lattice temperature. Magnified curve for 150 K shows the 1.818 eV PL used to track the SO transition as a function of Bi concentration. The peaks near 1.88 and 1.843 eV are leakage of forbidden Raman scattering.Reuse & Permissions

Figure 4

Transmission spectra for the 1.36% ${\mathrm{GaAs}}_{1-x}{\mathrm{Bi}}_x$ sample. The substrate is partially removed in the lower curve (red or light gray), and completely removed in the upper curve (blue or dark gray). Vertical arrows show critical point energies of GaAs taken from Ref. 11, and of ${\mathrm{GaAs}}_{1-x}{\mathrm{Bi}}_x$. The SO transition at RT for ${\mathrm{GaAs}}_{1-x}{\mathrm{Bi}}_x$ was estimated from Fig. 5 using the known temperature dependence of the GaAs band edge from Ref. 11.Reuse & Permissions

Figure 5

(a) Energies of the 150 K SO PL (squares) and band gap PL (circles) similar to Figs. 1, 3 for a set of 8 samples of varying bismuth concentration, after correction for strain-induced energy shifts. Solid lines are linear fits to the PL points and crosses are ER band gap energies, also strain corrected. (b) The spin-orbit splitting obtained by subtracting the band gap energies from the spin-orbit energies of (a). The dashed line is the linearly interpolated spin-orbit splitting using ${\Delta }_0=0.340\mathrm{eV}$ for GaAs, and 2.15 eV for GaBi. The solid line is a quadratic fit to the data, ${\mathit{\Delta }}_0={\mathit{\Delta }}_{\mathrm{interpolated}}-x(1-x)b$, with the bowing parameter $b=-6.0\mathrm{eV}$.Reuse & Permissions