Growth and optical absorption spectra of the layer‐type trichalcogenides ZrS₃ and HfS₃

Optical absorption measurements on single crystals of the layer trichalcogenides ZrS3 and HfS3 were made in the energy range of the intrinsic absorption edge. The crystals are mono‐clinic and have pronounced dichroism. Both compounds ZrS3 and HfS3 are semiconductors with band gap energies of about 2.8 and 3.1 eV, respectively. A simple model is proposed which explains the experimentally observed selection rules and which incorporates the symmetries of valence and conduction bands. Copyright © 1973 WILEY‐VCH Verlag GmbH & Co. KGaA