Single-atomic-layered quantum wells built in wide-gap semiconductors LnCuOCh (Ln=lanthanide, Ch=chalcogen) -: art. no. 155305

LnCuOCh (Ln=lanthanide, Ch=chalcogen) layered oxychalcogenides are wide-gap p-type semiconductors composed of alternately stacked (Ln(2)O(2))(2+) oxide layers and (Cu(2)Ch(2))(2-) chalcogenide layers. Energy band calculations revealed that Cu-Ch hybridized bands only spread in the (Cu(2)Ch(2))(2-) layers, which suggests that hole carriers in these bands are confined by the potential barriers formed by the (Ln(2)O(2))(2+) layers. Stepwise absorption spectra of a series of LnCuOCh experimentally verified that an exciton in the (Cu(2)Ch(2))(2-) layers shows a two-dimensional behavior. These theoretical and experimental results indicate that LnCuOCh has "natural multiple quantum wells" built into its layered structure.