Temperature and Bi-concentration dependence of the bandgap and spin-orbit splitting in InGaBiAs/InP semiconductors for mid-infrared applications

Replacing small amounts of As with Bi in InGaBiAs/InP induces large decreases and increases in the bandgap, E-g, and spin-orbit splitting, Delta(SO), respectively. The possibility of achieving Delta(SO)>E-g and a reduced temperature (T) dependence for E-g are significant for suppressing recombination losses and improving performance in mid-infrared photonic devices. We measure E-g(x, T) and Delta(SO) (x, T) in In0.53Ga0.47BixAs1-x/InP samples for 0 <= x <= 0.039 by various complementary optical spectroscopic techniques. While we find no clear evidence of a decreased dE(g)/dT (approximate to 0.34 +/- 0.06 meV/K in all samples) we find Delta(SO)>E-g for x > 3.3-4.3%. The predictions of a valence band anti-crossing model agree well with the measurements. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768532]