Intercalation-induced shift of the absorption edge in ZrS₂and HfS₂

Abstract

A strong shift of the fundamental absorption edge in TxZrS2 and TxHfS2 (T=Cu,Fe) single crystals was observed for 0<or=x<or=0.22. In each case larger shifts were observed for higher values of x. For similar values of x the shifts were larger for Fe than for Cu intercalates. Since these compounds remained semiconducting, the charge-transfer rigid-band model did not seem applicable. An alternative model was suggested.