I.V. Markevich

Some peculiarities of impurity diffusion in CdS crystals

Diffusion of Li, Cu and Ag in CdS crystals was investigated in different crystallographic directions by means of a technique based on defect drift in an electric field. A considerable diffusion anisotropy was observed for Cu and Ag: perpendicular to the c-axis diffusion of the former about one order faster and diffusion of the latter is several times slower than parallel to the c-axis. A similar diffusion anisotropy was also found in CdSSe and ZnCdS crystals. Peculiarities of Cu and Ag diffusion are discussed.

New insight on the interaction of self-activated and Mn-related emission centers in ZnS

The photoluminescence (PL) and PL excitation (PLE) spectra of undoped and thermally doped with Mn ZnS single crystals are studied. In the PL spectra, the bands caused by Mn-related and self-activated (SA) emission centers were observed. A number of narrow peaks whose intensity enhanced with increasing Mn content were found in the PLE spectra of SA emission. The same peaks were present in the PLE spectra of the Mn-related emission band. Some of these peaks were previously observed in the absorption spectra and attributed to Mn2+ ions. The appearance of Mn-related peaks in the PLE spectra of SA emission is explained by excitation transfer from the Mn2+ ions to SA emission centers. The conditions required for this transfer and possible mechanisms of the process are discussed.