Nonvolatile memory with molecule-engineered tunneling barriers

We report a novel field-sensitive tunneling barrier by embedding C-60 in SiO2 for nonvolatile memory applications. C-60 is a better choice than ultrasmall nanocrystals due to its monodispersion. Moreover, C-60 provides accessible energy levels to prompt resonant tunneling through SiO2 at high fields. However, this process is quenched at low fields due to highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap and large charging energy of C-60. Furthermore, we demonstrate an improvement of more than an order of magnitude in retention to program/erase time ratio for a metal nanocrystal memory. This shows promise of engineering tunnel dielectrics by integrating molecules in the future hybrid molecular-silicon electronics. (C) 2008 American Institute of Physics.