InGaBiAs/InP semiconductors for mid-infrared applications: Dependence of bandgap and spin-orbit splitting on temperature and bismuth content.

Replacing small amounts of As with Bi in InGaBiAs/InP induces large decreases and increases in the bandgap, Eg, and spin-orbit splitting, ΔSO, respectively. The possibility of achieving ΔSO>Eg and a reduced temperature (T) dependence for Eg are significant for suppressing recombination losses and improving performance in mid-infrared photonic devices. We measure Eg(x, T) and ΔSO(x, T) in In0.53Ga0.47BixAs1−x/InP samples for 0≤x≤0.032 by optical spectroscopy. While we find no clear evidence of a decreased dEg/dT (≈0.33±0.07meV/K in all samples) we find ΔSO>Eg for x>3.3–4.3%. The predictions of a valence band anti-crossing model agree well with the measurements. [ABSTRACT FROM PUBLISHER]