PHOTOLUMINESCENCE STUDY OF THE ONE-DIMENSIONAL MATERIAL ZRS3 AND ITS SOLID-SOLUTION ZR1-XHFXS3

The study of photoluminescence band-tail-localized excitons in ZrS3 an d in its solid solution Zr1-xHfxS3 confirms the existence of two polyt ypes for these one-dimensional materials. Fitting of the spectra, with a model proposed by Ouadjaout and Marfaing, associates a density of s tates proportional to exp[-(epsilon/epsilon(0))(3/2)] and implies both defect and compositional fluctuations. Gap energy, parallel and perpe ndicular to the chain direction, has been calculated in Zr1-xHfxS3, an d its variation with composition x is found to follow a quadratic law.