Optical Study of Phase Transition from Tetrahedrally into Octahedrally Coordinated MnS

Abstract

Abstract MnS thin films on glass substrates prepared by thermal vacuum evaporation show zincblende/wurtzite and rocksalt structure, respectively in dependence of the substrate temperature. The thermal‐treatment induced transition from the tetrahedrally (ZB/W) into the octahedrally (RS) coordinated phase is studied optically by photoluminescence, excitation, and absorption spectroscopy and by X‐ray diffraction measurements. Emission bands in the red and infrared spectral region are observed being characteristic for the tetrahedrally and octahedrally coordinated phase, respectively. The excitation due to energy transfer by Frenkel excitons is studied in various stages of the ZB/W → RS phase transition. As a result of this transition a shift of the absorption edge by about 300 meV to lower energies is found ascribed to a corresponding energy‐gap difference.