Fourier transform photoluminescence excitation spectroscopy of medium-bandgap Hg1-xCdxTe and InSb.

We report for the first time on Fourier transform photoluminescence excitation spectroscopy in the mid-infrared covering the wavelength range between 1 and 5.5 Mym. By studying a medium-bandgap Hgsub0.66Cdsub0.34Te bulk crystal and InSb bulk material, direct evidence for the excitonic nature of the luminescence transitions has been found in both cases. In addition, the excitation spectra on MBE-grown Hgsub1minusxCdsubxTe superlattices show the step-like density of states of the confined two- dimensional system.