Photoluminescence in pulsed-laser deposited GeGaSbS:Er films


The complex dielectric function, the Er3+ Stokes emission at ≈1540 nm and the upconversion photoluminescence at ≈990 nm of pulsed-laser deposited thin-film GeGaSbS:Er3+ were studied. The film shows ≈990 nm upconversion photoluminescence originating from the Er3+: 4I11/24I15/2 transition under a 1550 nm excitation. The compositional trends of the photoluminescence intensity are attributed to the presence of Er clusters which may lead to unfavorable concentrationquenching, radiation-trapping and reabsorption processes in the sulphur deficient films.