Homogeneous and inhomogeneous linewidths of excitons in partially ordered Ga0.52In0.48P

Abstract
We report picosecond four‐wave mixing experiments on Ga0.52In0.48P grown by organometallic vapor phase epitaxy on GaAs substrates. The spectral behavior of the homogeneous linewidth in the range of the inhomogeneously broadened band gap excitonic resonance is found to be different for a more disordered as compared to a partially ordered structure. Whereas the former shows the normal alloy behavior, the behavior of the partially ordered sample supports the assumption that its structure consists of ordered domains with varying degrees of order. This means, in particular, that the main origin of the inhomogeneous broadening is different for the disordered and ordered case. In addition, a polarization dependence of the four‐wave mixing signal is only observed for the more disordered sample.