Carrier location in low-bandgap Hg1-xCdxTe crystals, studied by photoluminescence

We report on Fourier transform photoluminescence studies, carried out on bulk Hgsub1minusxCdsubxTe. Using a double-modulation technique, luminescence in the 10 Mym range has been measured. The dependence of the luminescence spectra on temperature and excitation density has been studied. A single line with a FWHM of 130 cmhighminus1 is observed, which exhibits an anomalous increase of the intensity with rising temperature. In addition, a change of the lineshape and a large blue shift of the spectra of 6ksubB (0.52 meV Khighminus1) occurs. These observations are explained on the basis of alloy disorder. Assuming exponential band tails and considering the effect of carrier localization on the minority carrier lifetime, the experimental results are consistently explained.