Development of an optical storage system of semiconductor nanocxystal thin film

点击翻译按钮获取中文摘要

The principle and the mechanism of the optical memory using semiconductor nanoparticles are studied for developing an optical memory media. The fabrication process is also studied. It was already discovered by our previous works that the intensity of photoluminescence of thin films consisting of semiconductor nanoparticles increases with irradiating time of UV light. The only way to control the intensity of photoluminescence was the irradiating period. Therefore, the application of an optical memory was limited.We discovered that the increase ratio of the photoluminescence can be controlled by the intensity of irradiating light. The weak light can enhance the increase ratio more than the strong light. This result shows the possibility of multi-value recordings by controlling the intensity of irradiating light. Since the increase of photoluminescence is reversible, the multi-value recording is rewritable. It is concluded that higher density rewritable media than current double- value re … More cording such as 0 and 1 can be produced. The multi-value recordings and their reading can be done by a single wave of light. Therefore, a simple reading device is expected by employing a same optical head to both write and erase.A wet process must be developed in order to fabricate thin films of nanoparticles for large area and with high speed coating. The surface force on a particle and the Brownian force become dominant for smaller particles. However, those effects on the self-ordering of particles are not well understood experimentally. We have carried out the particle self-ordering during drying with considering the interaction forces among particles through the liquid surface. Then we realized that the self-ordering can be categorized to three patterns : (1) crystals such as hexagonal or tetragonal ordering, (2) random aggregates, and (3) dispersed crystals like a colonic crystal. Especially, the ordering state obtained from our model suggests that we can fabricate the thin films highly ordered by wet processes. This method can be applied to not only the fabrication of thin films of semiconductor nanoparticles but also other broad technology area. Less