High Density Data Storage Based on Ferroelectric Polymer Nanodot Arrays

When subjected to an electric field, the polarization of ferroelectric polymers can be switched between two states. The two states can be designated as “0” and “1”, while “0” and “1” are the basic codes in the binary information storage system. Therefore ferroelectric polymer can be used as memory.

The ferroelectricity originates from the ordered structure in the crystalline regions of ferroelectric polymers. To operate the memory devices at low voltage (<10 V), we have to minimize the film thickness to nanometer scale. However, in that case, the crystalline regions will become smaller, and the structure of the film will become disordered, which results in decreased ferroelectric performances. Besides, the polarizations of two adjacent memory bits can influence each other in the continuous ferroelectric films, which is defined as “cross-talk”.

In our paper, we found that compared with the the continuous films, the crystalline regions are more uniform and the structure are more ordered when the polymers are made crystallize in an alumina template bearing millions of pores with tens of nanometers. That ensures uniform and strong ferroelectric properties. What’s more, cross-talk is greatly decreased in the nanodot arrays compared with the continuous films and one-dimensional nano-grating structures. Assuming the ferroelectric nanodots (memory units) are arranged hexagonally, the data storage density is estimated to achieve a value of as high as 75 Gb inch^-2. That is to say, we can save a whole DVD on a chip whose size is smaller than 1/4 palm.