**Author details**

the interface states is quite fast leading to a poor retention. The endurance properties of the molecular memory devices are shown in **Figure 12e** and **f** [24]. Both devices exhib‐ ited excellent endurance characteristics with ±10 V P/E gate voltages and 500 and 100 μs

applying 500 μs P/E voltages. With shorter P/E voltages (100 μs), both devices still func‐

better than that of the conventional floating‐gate memory, and is resulted from the excel‐

less than 50% of the molecules in the SAM were effectively involved in the redox pro‐ cess, though the portion is slightly higher than that of the capacitor structure memory cell. Further research efforts are needed to increase the redox efficiency so as to lower the operation voltage and improve the operation speed. The memory density can be fur‐ ther increased with more carefully engineered molecules, and the demonstrated multibit memory concept is more reasonable and feasible than by just modulating the voltage level, as precise controlling of the charged states can be clearly defined and monitored with the

The properties of redox‐active molecules and the integration of molecular electronics in non‐ volatile memory technology have been systematically discussed. So far, redox‐active mol‐ ecules have already shown their potential and advantageous properties for future low‐power, high‐density, and high‐reliability nonvolatile memory. Solid‐state integration of the redox molecules in flash‐like nonvolatile memory devices enables the extension of the advantages afforded by the molecules to advanced electronic devices combined with universal semicon‐ ductor metrologies. Due to the intrinsic redox behavior of the molecules, large memory win‐

is about 10,000 times better than that of the conventional floating‐gate memory. Furthermore, discrete multibit charge storage can be enabled by mixing various redox molecules or using molecules with multiple redox states. The current main barriers are the CMOS compat‐ ibility and the process issues introduced with the molecular integration. The realization of future molecular memory applications still requires a combination of empirical fabrication and rational designs for particular molecular electronics devices toward sophisticated appli‐ cation. Upon this, the molecular electronics will no doubt be shedding more new lights on the micro‐/nanoelectronics society for creating next generation nonvolatile memory with

Q. Li would like to acknowledge the support of Virginia Microelectronics Consortium (VMEC).

dow with sufficient charge‐trapping density can be achieved, and the >10<sup>9</sup>

P/E operation cycles. Such excellent endurance is 10,000 times

P/E cycles by

endurance cycles

molecules [24]. However,

pulse width. Negligible memory window degradation was observed after 10<sup>8</sup>

lent reliability of the redox properties of the ferrocene and Ru<sup>2</sup>

tioned perfectly after 109

76 Redox - Principles and Advanced Applications

physically discrete redox states.

**5. Conclusions**

enhanced performance.

**Acknowledgements**

Hao Zhu<sup>1</sup> \* and Qiliang Li2

\*Address all correspondence to: hao\_zhu@fudan.edu.cn

1 School of Microelectronics, Fudan University, Shanghai, PR China

2 Department of Electrical and Computer Engineering, George Mason University, Fairfax, VA, USA
