Carbon nanocrystals for ultra high density memory and nano-scale sensors
Driven by the ever increasing need for high density digital memory at low cost, we have previously demonstrated the possibility to use carbon molecules in the form of fullerenes (C 60), also known as “buckyballs,” as an electrostatic non-volatile memory storage device. These devices employed the commonly used binary state for storage of digital information. In the course of this work CNS researchers have also found that they can employ C 60 nonvolatile memory cells in a CMOS type transistor structure to experimentally program four levels of charge storage per C 60 molecule corresponding to the different electrical states, C 60 0, C 60 1-, C 60 2-, and C 60 3-. The precise molecular size of C 60 results in a very sharp staircase like response curve. This paves the way for realizing ultra high density molecular memory, where multiple units of electronic charge can be stored on each molecule. This is the first demonstration that a CMOS circuit system can directly control and sense the reduced and oxidized states of molecules at the nano-scale, which could also lead to low cost, compact and highly sensitive chemical sensors.
Staircase type response curve of a C 60 molecule showing four levels of charge storage that could be used in high density multi-level molecular memory.
[Lead CNS Investigator: Kan group - Nanoelectronics Thrust, Center for Nanoscale Systems, Cornell University]
For additional information see:
- T.-H. Hou, U. Ganguly, and E. C. Kan, Programmable molecular orbital states of C 60 from integrated circuits, Appl. Phys. Lett. 89, article 253113, Dec. 2006.