Bound-Excitonic Emissions in Undoped and Mn-Doped ZnS Single Crystals
Excitonic emissions observed in undoped and Mn-doped ZnS single crystals with cubic modification have been investigated by means of the temperature dependence of photo-luminescence intensity and the doublet structure. Reflectance spectrum at 4.2 K indicates that an exciton dip appears at 3.803 eV and the longitudinal-transverse splitting energy of free exciton is about 4 meV when 4πβ is 1.05×10-2 and ∈ is 8.1, respectively. Thermal dissociation energy of the free exciton is estimated to be about 40 meV. Assuming that the zero-phonon line associated with an Mn emission is ascribed to an isoelectronic-trap bound exciton, the doublet structure and thermal dissociation process are reasonably interpreted.
KeywordsFree Exciton Excitonic Emission Doublet Structure Solid State Communication Thermal Dissociation Process
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