Photoluminescent and structural properties of CaS:Pb electron beam deposited thin films

The structural and optical properties of electron beam deposited CaS:Pb thin films were investigated as a function of annealing temperature and lead concentration. X-ray diffraction measurements show weak crystallinity for such layers. Although this improves with higher annealing temperatures, no difference in the grain size could be seen by means of atomic force microscopy. This can be explained by columnar growth or relaxation of strain. At high annealing temperatures (1000 degreesC for 2 min) and sufficiently high lead concentrations (0.74 at%), a bright blue photoluminescence could be observed. Excitation spectra were acquired showing different excitation bands.