Optical properties, bistability, and nonlinearity of evaporated ternary II-VI semiconductor thin films
Hans Joachim Eichler, Andreas Haase, A. Kummrow +6 more
Ternary II-VI semiconductors, like CdSxSe1-x or ZnxCd1-xS, were prepared by thermal evaporation of binary semiconductors from a double source. The influence of substrate temperature during thin film deposition and of thermal annealing in argon atmosphere on absorption edge steepness is studied. A high absorption edge steepness is advantageous to achieve large resonant optical nonlinearities, like absorption bistability and electronic nonlinearities. The position of the absorption edge can be tuned by choosing a proper film composition. Thermally induced optical bistability is demonstrated. Electronic nonlinearities are investigated in ns- and ps-pump-probe experiments. Fast bleaching with < 60 ps relaxation time is observed at the absorption edge. The maximum bleaching coefficient for CdS0.69Se0.31 films is 1.4 cm/kW at (lambda) equals 587 nm for pumping with (lambda) equals 377 nm. Annealing the films showed no effect on the relaxation time, but the bleaching coefficient was increased by a factor of five.
Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 4, 1993•0 citations