Two-photon-induced photoenhancement of densely packed CdSe/ZnSe/ZnS nanocrystal solids and its application to multilayer optical data storage

We report on a two-photon absorption-induced photoenhancement effect on a densely packed CdSe/ZnSe/ZnS core-shell semiconductor nanocrystal solid film. The enhancement is found to be irreversible without a noticeable blueshift in emission spectra, hence we attribute the enhancement to the photoannealing of interface defects rather than to the photo-oxidation or surface passivation by other molecules. The two-photon enhancement allows us to record the enhanced spots three dimensionally, hence demonstrating the feasibility of its application to multilayered optical data storage based on nanocrystal solids. © 2004 American Institute of Physics.