  The object of this article is to review the development of ultrahigh-density,
nanoscale data storage, i.e., nanostorage. As a fundamentally new type of
storage system, the recording mechanisms of nanostorage may be completely
different to those of the traditional devices. Currently, two types of
molecules are being studied for potential application in nanostorage. One is
molecular electronic elements including molecular wires, rectifiers, switches,
and transistors. The other approach employs nanostructured materials such as
nanotubes, nanowires, and nanoparticles. The challenges for nanostorage are not
only the materials, ultrahigh data-densities, fabrication-costs, device
operating temperatures and large-scale integration, but also the development of
the physical principles and models. There are already some breakthroughs
obtained, but it is still unclear what kind of nanostorage systems can
ultimately replace the current silicon based transistors. A promising candidate
may be a molecular-nanostructure hybrid device with sub-5 nm dimensions.
