Moreno, Miguel Angel

Zinc(1-x)manganese(x)sulfur is a ternary semiconductor compound which belongs to the family of diluted magnetic semiconductors (DMS). It has two crystalline phases: cubic for x < 0.10, and hexagonal for 0.10 < x < 0.50. Its energy gap is temperature and x dependent. The gap, ranging from 3.7 to 3.8 eV, is the largest of the DMS. These properties allow studies of the energy levels of the Mn^2+ ions in ZnS and their internal or ion-to-band transitions, by using photoluminescence. Samples with x = 0.01-0.50 were excited with the 5145A line of an Ar+ laser. The spectra, taken at temperatures between 10 and 300K, showed three bands: a band peaking at 2.12 eV was related to the 4T1 to 6A1 internal transition; a band peaking at 1.95-2.10 eV (depending on T) was related to the 4T1 to Gamma 1 5 ion-to-band transition; the origin of the third band, peaking at 1.65 eV, was discussed. A partial fourth band in the IR region was detected. The position of the 6A1 state with respect to the valence band was established.